Ascot Road, Watford€¦ · 16037-01-R02B Ascot Road, Watford – Transport Assessment i CONTENTS...

16037-01-R02B Ascot Road, Watford – Transport Assessment

Ascot Road, Watford Transport Assessment January 2017

Report – R02B

Prepared for:

Orion Land and Leisure

Prepared by:

Markides Associates

9th floor The Tower Building

11 York Road

London SE1 7NX

United Kingdom

+44 (0)20 7442 2225

http://markidesassociates.co.uk


Ascot Road, Watford

Transport Assessment

January 2017

Prepared for:

Orion Land and Leisure

Prepared by:

Markides Associates

9th floor The Tower Building

11 York Road

London SE1 7NX

United Kingdom

+44 (0)20 7442 2225

http://markidesassociates.co.uk


Copyright 2016 Markides Associates Ltd. The concepts and information contained in this document are the property of

Markides Associates. Use or copying of this document in whole or in part without the written permission of Markides

Associates constitutes an infringement of copyright.

Limitation: This report has been prepared on behalf of, and for the exclusive use of the client of Markides Associates, and

is subject to, and issued in accordance with, the provisions of the contract between the client and Markides

Associates. Markdies Associates accepts no liability or responsibility whatsoever for, or in respect of, any use of, or

reliance upon, this report by any third party.


i

CONTENTS

Page

1.0 Introduction 1

2.0 Planning Policy and Guidance 9

3.0 Existing Situation 17

4.0 Proposed Development 32

5.0 Trip Generation and Distribution 41

6.0 Traffic Impact 51

7.0 Summary and Conclusion 95

FIGURES Figure 1.1 - Site Location Plan

Figure 1.2 – Committed and Reasonably Foreseeable Development

Figure 3.1 – Existing land use traffic distribution AM peak

Figure 3.2 – Existing land use traffic distribution PM peak

figure 3.3 – Accessibility Plan

Figure 3.4 – Transport Infrastructure Plan

Figure 5.1 – Distribution Profile

Figure 5.2 – AM Peak development Distribution

Figure 5.3 – PM Peak development Distribution

Figure 6.1 - 2015 Buildings 1 and 2, Marlins Meadow Submission Observed Turning Movements AM Peak

Figure 6.2 - 2015 Buildings 1 and 2, Marlins Meadow submission Observed Turning Movements PM Peak

Figure 6.3 - 2016 Traffic Flows AM Peak

Figure 6.4 - 2016 Traffic Flows PM Peak

Figure 6.5 - 2021 Traffic Flows AM Peak

Figure 6.6 - 2021 Traffic Flows PM Peak


ii

Figure 6.7 - Cassiobridge Station Traffic Flows AM Peak

Figure 6.8 - Cassiobridge Station Traffic Flows PM Peak

Figure 6.9 - Ascot Road Community Free School Traffic Flows AM Peak

Figure 6.10 - Ascot Road Community Free School Traffic Flows PM Peak

Figure 6.11 - Buildings 1 and 2 Marlins Meadow AM Peak

Figure 6.12 - Buildings 1 and 2 Marlins Meadow PM Peak

Figure 6.13 - 2021 With Committed Development AM Peak

Figure 6.14 - 2021 With Committed Development PM Peak

Figure 6.15 - 2021 Baseline with Development AM Peak

Figure 6.16 - 2021 Baseline with Development PM Peak

Figure 6.17 – Masterplan site S2 AM Peak Distribution

Figure 6.18 – Masterplan site S2 PM Peak Distribution

Figure 6.19 – Masterplan site S3a AM Peak Distribution

Figure 6.20 – Masterplan site S3a PM Peak Distribution

Figure 6.21 – Masterplan site P5 AM Peak Distribution

Figure 6.22 – Masterplan site P5 PM Peak Distribution





Figure 6.27 – Masterplan sites AM Peak Distribution

Figure 6.28 – Masterplan sites PM Peak Distribution

Figure 6.29 - 2021 Baseline with masterplan AM Peak

Figure 6.30 - 2021 Baseline with masterplan PM Peak

Figure 6.31 - 2021 Baseline with masterplan with development AM Peak

Figure 6.32 - 2021 Baseline with masterplan with development PM Peak

Figure 6.33 – Woodshots Meadow High Tech site AM Peak

Figure 6.34 - Woodshots Meadow High Tech site PM Peak

Figure 6.35 - 2021 Baseline with masterplan with High Tech Site AM Peak

Figure 6.36 - 2021 Baseline with masterplan with High Tech Site PM Peak

Figure 6.37 - 2021 Baseline with masterplan with development with High Tech Site AM Peak

Figure 6.38 - 2021 Baseline with masterplan with development with High Tech Site PM Peak

Figure 6.39 –Development Distribution AM Peak No Station Scenario

Figure 6.40 – Development Distribution PM Peak No Station Scenario


iii

Figure 6.41 - 2021 With Committed Development AM Peak No Station Scenario

Figure 6.42 - 2021 With Committed Development PM Peak No Station Scenario

Figure 6.43 - 2021 Baseline with Development AM Peak No Station Scenario

Figure 6.44 - 2021 Baseline with Development PM Peak No Station Scenario

Figure 6.45 – Ascot Road Masterplan AM Peak No Station Scenario

Figure 6.46 – Ascot Road Masterplan PM Peak No Station Scenario

Figure 6.47 - 2021 Baseline with masterplan AM Peak No Station Scenario

Figure 6.48 - 2021 Baseline with masterplan PM Peak No Station Scenario

Figure 6.49 - 2021 Baseline with masterplan with development AM Peak No Station Scenario

Figure 6.50 - 2021 Baseline with masterplan with development PM Peak No Station Scenario

Figure 6.51 - 2021 Baseline with masterplan with High Tech Site AM Peak No Station Scenario

Figure 6.52 - 2021 Baseline with masterplan with High Tech Site PM Peak No Station Scenario

Figure 6.53- 2021 Baseline with masterplan with development with High Tech Site AM Peak No Station Scenario

Figure 6.54 - 2021 Baseline with masterplan with development with High Tech Site PM Peak No Station Scenario

DRAWINGS

16-037-200 - Ascot Road Suggested Pedestrian Crossing

16-037-201- Proposed undercroft parking access

16-037-202 - Vehicle swept path analysis – fire tender

16-037-203 - Vehicle swept path analysis – 7.5t box van

16-037-204 - Delivery and servicing / Car Club Provision

16-037-205 – Refuse Collection Strategy

16-037-207 - Ascot Road new / Morrisons access existing arrangement

16-037-208 - Ascot Road new / Morrisons access cumulative development proposed arrangement

16-037-210 - Ascot Road / Whippendell Road existing arrangement

16-037-211 - Ascot Road / Whippendell Road proposed arrangement


iv

APPENDICES

Appendix A - Cassiobridge Station Layout, Arup drawing crl-arp-ha-00-dr-d-0100

Appendix B - Ascot Road masterplan

Appendix C - Proposed site layout

Appendix D - Proposed undercroft layout

Appendix E - HHC TASR response

Appendix F - HCC pre-application response

Appendix G - Existing land use traffic surveys

Appendix H - Pedestrian comfort level assessment

Appendix I - Personal injury accident data

Appendix J - Car club package

Appendix K - TRICS output – private flats

Appendix l - TRICS output – affordable flats

Appendix M - Distribution calculations

Appendix N - Ascot road / Morrisons access traffic survey

Appendix O - Traffic model outputs

Appendix P - TRICS output – private flats No Station Scenario

Appendix Q - TRICS output – affordable flats No Station Scenario

Appendix R - Traffic model outputs No Station Scenario


1

1.0 INTRODUCTION

Preamble and Site Location

1.1 Markides Associates (MA) have been instructed by Orion (Cassiobridge) Limited

to prepare a Transport Assessment (TA) in support of their proposals for a

residentially led mixed use development proposal at a site located at Ascot Rd,

Watford, WD18 8AD.

1.2 The site is located within the authority boundary of Watford Borough Council

(WBC), with Hertfordshire County Council (HCC) being the relevant local highway

authority. The adjacent local authority, Three Rivers District Council (TRDC), is

located within 200m of the site to the west, with sites located within this adjacent

authority also reliant on the immediate local highway network that surrounds the

site.

1.3 A site location plan is attached as Figure 1.1. Figure 1.1 confirms that the site is

bound to the west by Ascot Road, an unclassified local access road, which

currently operates one-way southbound, and from which the existing site is

currently accessed. Ascot Road runs parallel with a dual-carriageway that is also

referred to as Ascot Road, which provides access to the wider Watford Business

Park and Croxley Green Business Park. For the purpose of this TA, the dual

carriageway is referred to as Ascot Road New, whereas the one-way southbound

section along the site frontage is referred to as Ascot Road Old. To the south, the

site is bound by Ascot Road Community Free School, which opened in 2014, and

an area of undeveloped land that is understood to temporarily hold cars from a

garage located elsewhere, accessed from Ascot Road Old. South of this site is a

Morrison’s supermarket that opened in late 2013, which shares an access road

with the school. To the east the site is bound by school playing fields, with which

there is no direct access.

Cassiobridge Station

1.4 To the north, the site is bound by an existing railway embankment, which, whilst

currently abandoned, is to form part of the Croxley Rail Link, accommodating

London Metropolitan services between Watford town centre and central London,

with full service operation intended for 2020. A new London Underground station


2

on this link will be introduced on vacant land directly opposite the site, which will

be called Cassiobridge Station.

1.5 Following a joint application by HCC and London Underground, deemed planning

permission for the Croxley Rail Link was granted in July 2013 via a Transport and

Works Act Order (reference TWA/12/APP/01), with subsequent planning

applications for the design of the station made to discharge various conditions.

These applications included, most notably, 14/01370/DISCON (condition 11),

concerned with highways access and landscaping to the station and associated car

park and 14/01540/DISCON (condition 12), concerned with a revised detailed

design of the station.

1.6 The new station will accommodate a surface level commuter car park, accessed

from the Ascot Road Old via an existing site access, serving approximately 156

spaces, with the contraflow cycle lane removed and the introduction of a new

3.5m wide shared use footway/cycleway along the eastern edge of the

carriageway, and therefore the subject site frontage. These proposals are set out

within a drawing prepared by Arup (reference CRL-ARP-HA-00-DR-D-0100), which

is attached as Appendix A, and which was submitted as part of planning

application reference 14/01370/DISCON. The drawing also confirms the intention

to introduce London Underground staff parking under the railway viaduct, and a-

vehicular drop off area immediately south of this, with an existing layby accessed

from Ascot Road New retained.

1.7 The original application was supported by an Environmental Statement (ES) and

TA, which established the impact the introduction of the station would have on

the local highway network. This documentation has been reviewed to inform the

analysis undertaken within this TA. It should be noted that traffic impact analysis

undertaken as part of the TA detailed that the station, and associated car park,

was not anticipated to generate a significant increase in vehicle movements on

the local highway network and indeed in some locations a reduction was

envisaged as a result of modal shift to the train.

1.8 The development has been prepared to ensure these station proposals are not

precluded. However, it is understood from discussions with HCC, that an amended

landscape and parking strategy is likely to be promoted within the near future.


3

Site Allocation

1.9 The site forms part of the Western Gateway Special Policy Area 6, Western

Gateway, as defined in WBC’s adopted Core Strategy (Local Plan Part 1).

1.10 Policy MXD4 of WBC’s emerging Site Allocations and Development Management

Policies document (Local Plan Part 2) also identifies the site as being appropriate

for mixed used development, encompassing the car holding area to the south and

the site of Cassiobridge Station.

1.11 The site also forms part of WBC’s emerging Croxley View and Ascot Road Study

Masterplan, with land parcel reference S1. The Masterplan identifies a number of

other adjacent land parcels as being appropriate for redevelopment, with varying

phases of delivery. A number of these sites have been included as committed

developments within subsequent traffic impact analysis. The Masterplan layout is

attached as Appendix B.

Existing Land Use

1.12 The site comprises both derelict land and a series of industrial / warehouse

buildings, currently occupied by a relocations and logistics firm (Class B8), ‘Eagle

Relocations,’ with access taken from Ascot Road Old.

1.13 Traffic surveys of the existing occupant have been undertaken to establish existing

trip generation demands, described in further detail within subsequent sections

of this TA.

Development Proposals

1.14 The development proposals are to demolish the existing buildings, remove the

existing points of access, and introduce a residentially led development, with 4

blocks accommodating a total of 485 units, with a mix of unit types and tenure as

summarised in Table 1.1 below, with proposed site layout attached as Appendix

C.


4

TABLE 1.1: ACCOMMODATION SCHEDULE

Unit Size Private Tenure Social Tenure Total

1 Bed 182 70 252

2 Bed 123 85 208

3 Bed + Duplex 10 15 25

Total 315 170 485

1.15 The development proposals include an undercroft car park, accessed from a new

simple priority junction with Ascot Road Old, with layout attached as Appendix D.

The car park accommodates approximately 185 car parking spaces, reflecting a

parking ratio of 0.38 spaces per unit.

1.16 The basement also includes secure and sheltered cycle parking and bin storage.

1.17 The development proposals also include an element of commercial floorspace,

accommodated within three small units at the ground floor of Blocks A and C, with

a total gross floor area (GFA) of 1,093sqm, but with no allocated car parking. It is

intended that two of the units will be promoted as offering flexible retail space,

with the remaining unit operating as a community use. The commercial units will

therefore provide a service directed at the immediate site residents, and on this

basis there is assumed to be no associated vehicular traffic generation, an

assumption that has been accepted by HCC.

1.18 For the purpose of the TA an opening year of 2021 is adopted.

Ascot Road Old Closure

1.19 The development proposals have been prepared to ensure the aforementioned

Cassiobridge Station proposals and their associated access strategies are not

precluded. The redevelopment of the site, however, offers the opportunity to

revisit the approved station landscape and access strategies, with a suggested

alternative proposal being the introduction of northbound access on the southern

section of Ascot Road Old, providing two-way access to the site and the

Cassiobridge Station car park. This would allow Ascot Road Old, north of the

station access, to operate as a shared surface, maintaining essential vehicle access


5

for delivery and service and emergency vehicles only, and two-way cycle access,

but providing an improved pedestrian link between the site and the station.

1.20 The TA therefore also undertakes a sensitivity test to consider the impact such a

proposal would have on the operation of the local highway network, so that

should this proposal materialise in the long term, there is some confidence that

the local highway network can accommodate the changes in traffic profiles.

1.21 To be clear, this does not form part of this specific development proposal and the

application should not be considered on that basis.

Pre-application Dialogue

1.22 Pre-application dialogue has been undertaken with HCC, with a TA Scoping Report

(TASR) submitted in November 2016 and subsequent response received from HCC

in the same month, attached as Appendix E, which set out HCC’s requirements

for the TA.

1.23 The TASR set out the assumptions and methodologies that would be adopted

within this TA, including study area, trip generation and distribution calculations

and traffic impact scenarios.

1.24 A further response was received from HCC’s term consultant, attached as

Appendix F, which provided confirmation that the methodology for calculating

residential trip generation was acceptable.

Cumulative Impact

1.25 HCC’s response to the TASR set out requirements with regards to a cumulative

impact assessment, to include both committed developments and developments

that are reasonably foreseeable within the immediate future, identifying specific

sites that should be included.

1.26 The traffic impact analysis included within this TA has therefore adopted such an

approach, considering a number of different development scenarios, thus

allowing the inspecting authorities to understand which particular proposal and

scenario is having the most significant impact on the local highway network.


6

1.27 Whilst further detail is provided within subsequent sections of this TA, the

following scenarios have been considered, with location of committed

development or reasonably foreseeable sites indicated on Figure 1.2.

2016 existing year, informed by 2015 traffic counts undertaken in support of

TRDC application reference 15/1427/FUL, Buildings 1 and 2, Marlins Meadow

2021 future year baseline, encompassing the following committed

developments:

o Cassiobridge Station

o Ascot Road Free School, WBC application reference 12/00792/OUTM

o Buildings 1 and 2, Marlins Meadow, TRDC application reference

15/1427/FUL

2021 future year baseline (as above) plus development proposal

2021 future year baseline (as above) plus Ascot Road Masterplan,

encompassing the following sites:

o S2 – 100 residential units

o S3a – 125 residential units

o P5 – 35 residential units

o P6 – 6,200sqm B1a office space

o P7 – 40 residential units

2021 future year baseline plus Ascot Road Masterplan (as above) plus

development

2021 future year baseline plus Ascot Road Masterplan plus TRDC’s

Woodshots Meadow High Tech Site emerging proposal


Woodshots Meadow High Tech Site (as above) plus development

1.28 With regards to the TRDC Woodshots Meadow High Tech site, following direction

by WBC, MA have been in consultation with the appointed transport consultant


7

for that emerging development proposal and have therefore sourced their

estimated trip generation for that land use direct.

1.29 Where necessary, the TA will consider any mitigation that is necessary to negate

the specific impact of the development proposals on the local highway network.

The TA also considers the additional mitigation that might be necessary to

accommodate the wider cumulative impact.

1.30 From the outset, it should be highlighted that the proposals for the Woodshots

Meadow High Tech site are for a significant scale B1 Office space and car parking,

and that the traffic impact associated with the proposals are significant when

compared with the specific development proposals considered within this TA. Any

requirement for mitigation of the cumulative impact would, therefore, need to be

proportional to this scale of impact.

1.31 Whilst a number of other sites are identified within the Ascot Road Masterplan,

these have been rejected on the basis they will not have a direct vehicular

connection with the Ascot Road road network, being accessed from Croxley View,

e.g. S3b/S3c, and/or are currently operating with commercial success, meaning

they are unlikely to be available for redevelopment within the near future e.g.

PS2/PS3.

No Cassiobridge Station Scenario

1.32 Our understanding is that the Metropolitan Line Extension, and therefore the

introduction of Cassiobridge Station, is a committed and funded development

that will be delivered. Indeed enabling works associated with the proposals are

already underway. The scale and characteristics of the development proposal,

including in particular the proposed car parking ratios, are influenced by the

resultant improved accessibility.

1.33 However, should there be any concerns that Cassiobridge Station will not in fact

be delivered, an additional, ‘no-station,’ traffic modelling scenario has been

assessed within this TA. The ‘no station’ scenario was not identified within the

TASR. This scenario has adopted more robust vehicular trip rates than those

adopted within the scenarios where the station is in place. That is not to say that

residents will not be able to travel by London Underground as Croxley Station is


8

located approximately 1.4km walk distance from the site, which is readily

achievable for most able-bodied residents. Furthermore, a transport strategy

could be implemented that improves bus frequencies between the site and the

station. The analysis will seek to demonstrate that should the station not be

developed, the local highway network will have capacity to accommodate the

additional vehicle movements generated by the subject site, with mitigation

strategies implemented where necessary.

1.34 The robust trip rates are applied to both the subject site and other sites that form

part of the Ascot Road Masterplan, which have been included within this TA as

reasonably foreseeable developments under cumulative development scenarios.

1.35 The testing of this scenario will not however extend to multimodal impact.

TA Structure

1.36 Following this introduction, the remaining TA chapters are structured as follows;

Section 2 identifies relevant national, regional and local transport related

planning policy, against which the development proposals will be

considered;

Section 3 describes the site location, existing accessibility and transport

infrastructure that serves the site;

Section 4 describes the development proposals in detail including scale,

mix, layout pedestrian/cycle/vehicular access, delivery and servicing, car

parking and cycle parking;

Section 5 undertakes a multimodal trip generation assessment and

distribution analysis;

Section 6 undertake a traffic impact analysis;

Section 7 provides a summary and conclusion.

Other Documentation

1.37 In addition to this TA, a Travel Plan (TP) has also been produced and will be

submitted as a stand-alone document as part of the planning application, but

should be read in conjunction with this report.

1.38 The TP sets out a range of management strategies and a number of measures to

support and encourage sustainable travel by future residents, including the


9

introduction of an Applicant funded car club and car share database in order to

encourage reduced car ownership levels.

1.39 In addition to this TA, the scale of development has warranted the preparation of

an ES in support of the planning application, within which there is a Transport

chapter.

1.40 An ES Scoping Opinion was prepared by the project team planning consultant, JLL

and submitted to WBC, which included a list of suggested sites to include within

the cumulative assessment. A response to the Scoping Opinion was received from

WBC dated 21st November 2016. With regards to transport, this Scoping Response

provided further confirmation in relation to cumulative impact assessment and

included comments from Transport for London (TfL) that construction activity

associated with the Croxley Rail Link should be considered. The Scoping Response

also provided comments from HCC, which referenced that the TA should be

prepared in accordance with HCC guidance. The Transport chapter identifies the

sites that were identified within the Scoping Opinion that have not been included

within the cumulative impact scenario.


10

2.0 PLANNING POLICY AND GUIDANCE

Introduction

2.1 The following section reviews key reference points within transport related

planning policy at national, regional and local levels to ensure specific policies are

complemented by the development proposals.

National Policy National Planning Policy Framework (NPPF), March 2012

2.2 The NPPF, which replaced Planning Policy Guidance 13: Transport 2011, sets out

Government planning policy, provides a framework within which local planning

policies should be produced and is a material consideration in planning decisions.

2.3 With regards to transport, the NPPF identifies that all developments which

generate a significant amount of movement should be supported by a TA or

Transport Statement and that planning decisions should take account of whether:

The opportunities for sustainable transport modes have been taken

up, depending on the nature and location of the site, to reduce the

need for major transport infrastructure;

Safe and suitable access to the site can be achieved for all people; and

Improvements can be undertaken within the transport network that

cost effectively limits the significant impacts of the development.

Development should only be prevented or refused on transport

grounds where the residual cumulative impacts of development are

severe.

2.4 The NPPF states that planning decisions should ensure that developments

generating significant movements are located where the need to travel will be

minimised and the use of sustainable modes can be maximised, giving priority to

pedestrian and cycle movements and creating safe and secure layouts which

minimise conflicts between traffic and cyclists or pedestrians.

2.5 With regards to car parking, the NPPF does not include any standards and

recommends that local planning authorities should set standards based on the


11

accessibility of the development, availability of public transport and local car

ownership levels.

Planning Practice Guidance: Travel plans, transport assessments and

statements in decision-taking (PPG), March 2014

2.6 PPG provides more detailed planning guidance to support the NPPF and states

that transport planning submissions can contribute to:

encouraging sustainable travel;

lessening traffic generation and its detrimental impacts;

reducing carbon emissions and climate impacts;

creating accessible, connected, inclusive communities;

improving health outcomes and quality of life;

improving road safety; and

reducing the need for new development to increase existing road

capacity or provide new roads

Adopted Regional Policy

Local Transport Plan 3 2011

2.7 The Local Transport Plan (LTP) is a statutory document that sets out the County

Council’s vision and strategy for the long-term development of transport in the

county. HCC adopted their third Local Transport Plan (LTP3) in 2011. The key

transport issues in Hertfordshire remain the same: tackling peak-time congestion,

maintaining roads, reducing casualties, supporting economic growth and

maintaining access to key services.

2.8 With regards to development, under their development control responsibility,

HCC require the transport and safety implications of development proposals to be

considered, require developments to reduce the need to travel and ensure

alternative modes are promoted and require the impact of movement demand

generated by developments to be mitigated. HCC adopt a threshold of 80

residential units, above which a TA and TP will be required.


12

2.9 Development will be resisted that result in an increase in accident risk, a

significant increase in peak hour road congestion or a significant change in the

amount or type of traffic using local or rural roads.

Roads In Hertfordshire

2.10 Roads in Hertfordshire (RIH) is HCC’s Design Guide which needs to be considered

when designing access proposals and the internal site layout.

Adopted Local Policy

Watford District Plan 2000 Saved Policies

2.11 WBC’s Local Plan sets out the policies to guide development throughout the

borough. The Local Plan consists of the Core Strategy 2006-2031 (Part 1), adopted

January 2013, and saved policies of the District Plan 2000.

2.12 With regards to transport related planning policy with the District Plan saved

policies, Policy T10 Cycle Parking Standards states that WBC will expect all new

developments to make provision for cyclists that is conveniently located, secure,

and waterproof either on a unit-by-unit basis or, where this is not appropriate,

communally. For residential land uses, a minimum cycle parking standard of 1

space per unit is adopted. For commercial uses, a general standard of 1 employee

space per 10 employees is adopted, with additional short term provision required

for visitors.

2.13 Policy T21: Access and Servicing, details a requirement for development proposals

to include adequate provision for access/egress and servicing arrangements.

2.14 Policy T22: Car Parking Standards, details a requirement for all developments to

comply with maximum parking standards, which is based on a set of accessibility

zones. The site is identified as being located within zone 4, the most inaccessible

urban zone within the district. However, this assessment does not take into

account the introduction of Cassiobridge station, which will significantly increase

the accessibility rating of the site.

2.15 Notwithstanding this, the policy continues and states that, ‘non-residential

development will be expected to provide sufficient on-site parking to meet

operational needs and the needs of disabled motorists.’ With regards to residential


13

car parking, the adopted policy states that, ‘reduced provision may be acceptable

for high-density residential development in appropriate locations.’

2.16 Policy T24: Residential Development, states that ‘planning permission will only be

granted for residential use where the full parking needs generated can be met on

site, and off the public highway unless the site is in a suitable Town Centre site or

other location with good access to passenger transport’. Notwithstanding this, the

supporting narrative to this policy states that significantly lower levels of parking

provision may be acceptable where demand for parking is likely to be less and

tendency for overspill on street can be controlled, specifically citing high density

housing in town centres as an example. Based on the site being located within

Zone 4 of WBC’s parking map, the following maximum car parking standards are

therefore relevant:

1 bed units, 1.25 spaces per unit

2 bed units, 1.5 space per unit

3 bed units, 2.25 spaces per dwelling

2.17 Notwithstanding these residential car parking standards, Policy T26: Car Free

Residential Development, states that ‘car free residential development will be

considered in suitable locations, which are highly accessible by passenger

transport, close to amenities and services, subject to the provision of satisfactory

site covenants, on-street parking controls and measures to control displaced

parking in adjacent areas.’ The site benefits from each of these characteristics

being in place, apart from the existence of on-street parking controls.

Watford’s Local Plan – Part 1 – Core Strategy 2006-2013, January 2013

2.18 WBC Core Strategy sets out the key elements of the council’s planning vision and

spatial strategy for the borough.

2.19 The Core Strategy identifies a number of “Special Policy Areas” (SPAs) which form

an important part of the spatial strategy, with the site being located within Policy

SPA6 – Western Gateway. These areas have special policy status due to there

being a significant level of change expected in the area, with Policy SS1: Spatial

Strategy, detailing that development within these locations is unlikely to have

serious harm to character or amenity as they have good access to public transport

and local facilities. Policy SS1 also identifies that the transport strategy in


14

association with these SPAs is to focus on improvements to the public transport

network and encouraging cycle and walking.

2.20 In terms of transport, Policy T2 – Location of New Development – states that ‘new

development should be located in close proximity to sustainable transport nodes

and local centres or the town centre where facilities can be accessed without the

need to travel by private car.’ Policy T2 continues and states that, ‘to be considered

accessible by bus services, sites should be within 400m of a bus stop where a

frequent bus service operates. Frequent bus services are considered to be routes

where roads are served by 5 or more journey each way per day Monday to

Saturday.’

2.21 Policy T3: Improving Accessibility, states that all developments should be

accessible to people with disabilities and reflect a hierarchy that favours the most

sustainable forms of travel, walking and cycling, over private cars. Furthermore,

all developments should be accompanied by a TP.

2.22 Policy T4: Transport Assessments, states that new developments should be

accompanied by a TA in accordance with relevant industry guidance, which this

document therefore satisfies.

2.23 The Core Strategy also identifies that as part of the Development Management

policies document, the council will revise its current parking strategy and will

specifically;

Restrict the amount of car parking which is part of new development;

and

Restrict on-street parking through the use of Controlled Parking

Zones.

Emerging Local Plan

Local Plan Part 2 - Site Allocations and Development Management

Policies

2.24 WBC are currently preparing the Local Plan 2006-2031 Part 2 - Development

Management Policies and Site Allocations document, the publication version of

which was recently the subject of public consultation. Once adopted, this will

replace saved policies of the Watford District Plan 2000.

https://www.watford.gov.uk/info/20012/planning_and_building_control/135/planning_policy/3


15

2.25 Policy SPMX1: Special Policy Areas reaffirms the SPA’s that are identified within

the Core Strategy Part 1, including SPA6. The document also references the site

under policy SPMX2: Mixed Use Allocations Policy, as appropriate for a mixed use

development including up to 400 homes, encompassing the Cassiobridge Station

site and the vacant site to the south.

2.26 With regards to transport, Policy T6: Car Parking Provision states that all

developments should provide an appropriate level of parking in line with

standards, which are based on the accessibility of the site. The policy states

however that, ‘Flexibility on the recommended standards will be considered

positively for ‘car lite’ developments in close proximity to major transport

infrastructure where secure cycle storage is provided.’ The policy continues and

states that new developments will be exempt from applying for parking permits

within adjacent CPZ’s and that there should be 25% additional unallocated visitor

parking provision. The policy continues and states, ‘where car parking provision

does not adhere to the suggested guidance, provision of dedicated car club spaces

and vehicles and secure cycle storage is recommended. Provision for car clubs will

be expected for residential development where more than 20 parking spaces are

proposed.’

2.27 The emerging standards adopt a more simplified approach to accessibility, with

two zones identified based on proximity to rail stations and a minimum number

of bus services, with only the town centre falling within zone 1 and the rest of the

district, including the site location, falling within zone 2. The relevant zone 1/zone

2 residential car parking standards are therefore as follows:

1/2 bed units, 0.75/1.25 spaces per unit

3+ bed units, 1/2.25 spaces per unit

2.28 Policy T7: Car Clubs and Charging Points for Low Emission Vehicles, that that such

provision should be included within new developments, with 1:10 active provision

and 1:10 passive provision.

2.29 Policy T8: Cycle Parking Provision requires new developments to provide

conveniently located, safe to use, secure and weatherproof cycle parking, with

ratios that reflect the same standards as identified within the District Plan above.


16

2.30 Policy T9: Access and Servicing requires all developments to provide suitable

access arrangements for all user groups that are envisaged to access a site,

including delivery and servicing and emergency vehicles.

Croxley View/Ascot Road Study Masterplan.

2.31 WBC have recently published the Croxley View/Ascot Road Study Masterplan,

which was subject to public consultation up to early October 2016, which seeks

to provide a framework to facilitate redevelopment within the area.

2.32 The site is identified within the masterplan under site reference S1, envisaged to

accommodate 400 units, with cumulative development of up to 850 units within

early phases.

2.33 It is understood that no traffic modelling or transport infrastructure studies have

been undertaken to inform this masterplan.

Policy Compliance

2.34 In terms of policy compliance, the application is supported by this TA, which

assesses the potential transport impacts associated with the development

proposals.

2.35 The TA demonstrates that the site is located in a highly accessible location, both

in terms of proximity to existing social and sustainable transport infrastructure,

justifying the principle of residential development in this location.

2.36 This accessibility will only improve in the immediate future, with the committed

introduction of a London Underground station directly opposite the site, offering

frequent services into both central London and Watford Junction, from which

ongoing regional and national service connections can be accessed.

2.37 Residents, employees, and visitors will not therefore be wholly reliant on the

private car to travel to/from the site, which has influenced the proposed

restrictive car parking strategy for the site.


17

2.38 The proposed restrictive car parking strategy will be supported by the

introduction of a car club at the site and secure and sheltered cycle parking that

exceeds the minimum policy requirement. Any concerns regarding potential

parking overspill within the adjacent residential communities could be addressed

by the implementation of additional Controlled Parking Zones, which the

Applicant would be willing to contribute toward, although such a strategy is highly

likely to be necessary anyway to prevent commuters using Cassiobridge Station

from parking on-street and avoiding parking charges within the associated

commuter car park.

2.39 The TA demonstrates that based on the proposed car parking strategy the

additional traffic impact associated with the scale of development can be

accommodated within the local highway network, albeit with some minor

mitigation at off-site junctions.

2.40 Finally, the TA demonstrates that the site can be readily accessed by all user

groups, with a shared surface within the site that can be used by emergency and

infrequent service and delivery vehicle movements.

2.41 The development proposals promote a car parking strategy that reflects the

accessibility of the site location, and which ensures that there will be no material

worsening of the capacity of the immediate local highway network.

2.42 The TA demonstrates that the site can be readily serviced, is accessible to a range

of user groups, and provides an appropriate level of cycle parking provision.


18

3.0 EXISTING SITUATION

Introduction

3.1 This section of the TA provides a detailed review of the site location, existing

operation and transport infrastructure that serves the site.

Site Location

3.2 The site is located on the western edge of Watford, approximately 2.15km

(straight-line distance) from Watford town centre, 2.5km (straight line distance)

from Watford Junction and 3.15km from Rickmansworth.

3.3 A site location plan is attached as Figure 1.1. Figure 1.1 confirms that the site is

bound to the west by Ascot Road Old, an unclassified local access road, which

currently operates one-way southbound, and from which the existing site is

currently accessed. Ascot Road Old runs parallel with a dual-carriageway Ascot

Road New, which provides access to the wider Watford Business Park and Croxley

Green Business Park. To the south, the site is bound by Ascot Road Community

Free School, which opened in 2014, and an area of undeveloped land that is

understood to temporarily hold cars from a garage located elsewhere, accessed

from Ascot Road Old. South of this site is a Morrison’s supermarket that opened

in late 2013. The Morrisons site and the car holding site are separated by an access

road that forms a simple priority junction with the Ascot Road Old and a

roundabout junction with Ascot Road New. To the east the site is bound by school

playing fields, to which there is no direct access. The site is bound to the north by

the derelict railway line that will form part of the Croxley Rail Link.

3.4 Access to both sections of Ascot Road is taken from a roundabout junction with

the A412 Rickmansworth Road, which in turn provides access to Watford town

centre, and the strategic highway network, with junction 17 of the M25

approximately 7km to the west, accessed via Rickmansworth.

Existing Land Use


buildings, currently occupied by a relocations and logistics firm (Class B8), ‘Eagle

Relocations,’ with access taken from Ascot Road Old.


19

3.6 The existing land use and its associated demands are presented in Photo 1 and

Photo 2.

3.7 Traffic surveys of the existing occupant were undertaken in October 2016 in order

to establish the existing vehicular trip generation, against which the proposals will

be compared. The results of these surveys in terms of peak hour and daily traffic

flows are summarised below in Table 3.1, with survey outputs attached as

Appendix G.

TABLE 3.1: EXISTING OCCUPANT OBSERVED TRIP GENERATION

Hour Arrival Departure Total

08:00-09:00 7 1 8

17:00-18:00 4 12 16

24 Hour 70 81 151

3.8 Table 3.1 demonstrates therefore that the existing occupant does not generate a

significant amount of vehicle movements, either during traditional peak periods

or across the day. The proportion of daily vehicle movements that were classified

as either OGV1/2 was however found to be 16% of the total traffic generation,

some 25 daily vehicle movements.

Photo 1 – The existing Eagle Relocation industrial /

Warehouse buildings

Photo 2 – Existing Eagle Relocation vehicles

parked on Old Ascot Road


20

3.9 The anticipated distribution of these peak hour movements across the local

highway network is presented as Figures 3.1 and 3.2. This distribution profile is

taken from the TA that was prepared in support of the Buildings 1 and 2, Marlins

Meadow, TRDC application reference 15/1427/FUL, which was based on origin

destination Census 2011 Journey to Work data for employees working within

adjacent wards.

Site Accessibility

3.10 The site benefits from being located within close proximity of a range of social

infrastructure that acts as typical trip attractors for residents, including education,

health, leisure, convenience retail facilities and employment land uses.

3.11 Examples of this social infrastructure, and their associated walk distance, are

detailed below in Table 3.1 and Photos 3.3-3.6, as well as being indicated on the

attached Figure 3.3.

Photo 3 – Ascot Road Community

Free School situated directly adjacent

to the south east of the site.

Photo 4 – Croxley Green Business

Park on Hatters Lane. Photo 5 – Bridgewater Pharmacy

situated on Printers Ave


21

TABLE 3.1: TRIP ATTRACTORS

Attractor Land Use Site Assumed Walk Route Approx. Walk

Distance

Education

Ascot Road Community Free

School Ascot Rd 90m

St Anthony’s Roman Catholic

Junior School Ascot Rd, Croxley View 750m

Westfield Academy Secondary

School and 6th Form Ascot Rd, Croxley View 780m

Food Retail Morrisons Ascot Rd 160m

Budgens Ascot Rd, Whippendell Rd 380m

Leisure

Brewers Fayre Rising Sun

Restaurant Ascot Rd 220m

The Pump Gym Ascot Rd, Greenhill Crescent 735m

Post Office Ascot Rd, Croxley View, Tolpits Ln 990m

Cassiobridge Park

Ascot Rd, Whippendell Rd,

Rickmansworth Road, Gade

Avenue

1.2km

King George V Playing Fields Ascot Rd, Croxley View, Tolpits Ln 1.4km

Holywell Community Centre Ascot Rd, Croxley View, Tolpits Ln 1.45km

Watford Football Stadium Ascot Road, The Gateway, Sydney

Rd, Hagden Ln, Vicarage Rd 1.9km

Intu Watford Shopping Centre

Ascot Rd, Whippendell Rd,

Marlborough Rd, Market St, High

St

2.5km

Watford Town Centre Ascot Rd, Whippendell Rd,

Marlborough Rd, Market St 2.4km

Employment

Croxley Green Business Park Ascot Rd, Hatters Ln 450m

Watford Business Park Ascot Rd, Greenhill Crescent 450m

Wolsey Business Park Ascot Rd, Croxley View, Tolpits Ln,

The Ebury Way 1.3km

Watford Town Centre Ascot Rd, Whippendell Rd,

Marlborough Rd, Market St 2.4km

Health

Park End Surgery Ascot Road, The Gateway, Printers

Ave 340m

Bridgewater Pharmacy Ascot Road, The Gateway, Printers

Ave 350m

Watford General Hospital Ascot Road, The Gateway, Sydney

Rd, Hagden Ln, Vicarage Rd 1.8km


22

3.12 Table 3.1 therefore confirms that a range of land uses are located within close

proximity, which ensures that these trip attractors can be accessed by modes

other than the private car and realistically on foot, thereby reflecting fundamental

requirements of national, regional and local planning policy for creating

sustainable communities.

3.13 Indeed the Chartered Institute of Highway’s and Transportation’s (CIHT) March

2015 guidance document, ‘Planning for Walking,’ states that ‘walkable

neighbourhoods’ are those with a typical catchment of around 800m, with many

of the key identified land uses being within this walk distance threshold.

Pedestrian and Cycle Infrastructure

3.14 Pedestrian access to the site is from the western boundary, via an established

street-lit footway network along Ascot Road Old, which has an approximate width

of 3m. This footway network connects with Whippendell Road to the north and

Watford Business Park, Croxley Green Business Park and Croxley View residential

estate to the south, via Morrisons, with the Ascot Road Old footway provision

indicated on Photo 6.

3.15 Pedestrian severance caused by the volume of traffic on the local highway

network is mitigated by a number of informal and signalised crossing points

within proximity of the site. This includes toucan crossings located north of

the site on Ascot Road New, Whippendell Road and Rickmansworth Road, and

zebra crossings located adjacent to Ascot Road Community Free School,

supported by generous footway widths in this location, indicated on Photo 7.

Photo 6 – The existing footway bordering the west of the site.

Photo 7 – The public realm improvements to the south east of the site.


23

3.16 South of the site, a shared use pedestrian/cycle link connects Watford

Business Park with the Croxley View residential estate, with a similar facility

providing a southbound route toward Tolpits Lane, which also accommodates

a toucan crossing.

3.17 Immediately north of the railway embankment, an alternative pedestrian

footpath provides a link from Ascot Road Old with a development referred to

as The Gateway, which links with Sydney Road to the east and Whippendell

Road to the north via Printers Avenue.

3.18 In terms of cycle access, much of the pedestrian network described above is

essentially a shared use facility with cyclists, supported by formalised cycle

lanes and signage.

3.19 Whilst Ascot Road Old operates one-way southbound to all traffic movements,

Ascot Road Old also accommodates a northbound contraflow cycle lane,

indicated in Photo 8, which allows cyclists to negotiate Ascot Road New via an

aforementioned toucan crossing.

Photo 8 – Contraflow cycle lane on Old Ascot Old.


24

3.20 To the south, cyclists can take the Morrisons service road to connect with the

shared use facility toward Croxley View, and Tolpits Lane, from which access

to the Ebury Way traffic free cycle route between Watford town centre and

Rickmansworth is possible, also providing access to the Grand Union canal

towpath and forming part of the national cycle network, indicated in Photos

9,10 and 11.

3.21 In terms of travel distances, cycling is considered an appropriate mode of

travel for journeys up to 5km. In this regard the whole of Watford town centre

is within this cycle distance threshold. Cycling will therefore be promoted

within the standalone TP that will be submitted as part of the planning

application, with a range of measures implemented to encourage this mode of

travel.

3.22 In terms of existing pedestrian and cycle demands within the local highway

network, a series of surveys were undertaken on Thursday 13 th of October,

including peak hour counts on Ascot Road Old along the site frontage, the

Croxley View shared use footway/cyclepath and the Tolpits Lane toucan

crossing, with results summarised below as Table 3.2.

Photo 9 – Croxley View shared pathway and Tolpits Lane toucan

crossing

Photo 10 – The Ebury Path and National Cycle Route 6/61 links

Photo 11 – The Grand Union Canal towpath, Whippendell Wood

Walk and the Croxley Green Boundary Walk path.


25

TABLE 3.2: OBSERVED PEDESTRIAN/CYCLE DEMANDS

Location

Ascot Road Old Eastern Footway

Pedestrian Movements

Croxley View Shared Use

Footpath/Cyclepath

Pedestrian Movements

Croxley View Shared Use

Footpath/Cyclepath Cycle

Movements

Tolpits Lane Toucan Crossing Pedestrian

Movements

Tolpits Lane Toucan Crossing

Cycle Movements

Time 08.00-09.00

17.00-18.00

08.00-09.00

17.00-18.00

08.00-09.00

17.00-18.00

08.00-09.00

17.00-18.00

08.00-09.00

17.00-18.00

Two-

Way

Flows

180 93 251 81 17 13

55 (49 crossing

on green)

23 (17 crossing

on green)

16 (14 crossing

on green)

22 (16 crossing

on green)

3.23 Table 3.2 therefore indicates that the Ascot Road footway has significant

reserve capacity to accommodate additional demand, as will the Croxley View

shared use facility. The Tolpits Lane signalised crossing was observed to be

called 27 times in the AM peak and 22 in the PM peak.

3.24 Along the Croxley View shared use facility, pedestrians were observed to

constantly spill into the adjacent cycle lanes, using the area as a shared space,

with the number of cycle movements allowing such activity to occur.

Pedestrian Comfort Guidance Assessment

3.25 To establish if the existing footway widths in this location are appropriate for

this existing scale of demand, an assessment has been undertaken using

Transport for London’s Pedestrian Comfort Guidance Assessment (PCGA). A

PCGA is undertaken to ensure that the design of pedestrian footways are

appropriate for the volume and type of users of that environment and is

applicable to evaluating both a new or existing footway. Going further than a

traditional Fruin Level of Service assessment, which simply assesses crowding,

the PCGA takes into account user perceptions, different user behaviour within

a variety of area types and includes the real impact of street furniture.

3.26 Two locations have been considered, the Ascot Road Old footway along the

site frontage and the shared use footway/cycleway route toward Croxley

View.


26

3.27 For Ascot Road Old, a 2m wide footway is assumed, which is reflective of any

part of the footway along the site frontage, which is in the main free of street

furniture that reduces the effective width. For Croxley View, whilst

pedestrians were observed to use both the footpath and demarked cycle lanes

widths, a footpath width of 2m is assumed, reflecting a worst case scenario,

with all pedestrians therefore using a narrower footpath link. For both

locations, a building edge and kerb is assumed.

3.28 Following the PCGA methodology, the location type has been assumed to be

Full Footway Width and the area type has been assumed to be High Street and

there is assumed to be no static activity.

3.29 In terms of results, TfL’s guidance document identifies Pedestrian Comfort

Level Categorisations of A to F, where ‘A-‘ to ‘A+’ are ‘comfortable for all

areas,’ with ‘plenty of space for people to walk at the speed and the route that

they choose.’ TfL’s guidance document also states that the minimum

Pedestrian Comfort Level Categorisation that should be achieved for all area

types is ‘B+,’ at peak hour flow levels and that this level ‘provides enough

space for normal walking speed and some choice in routes taken’.

3.30 Appendix H presents the results of the assessment, which concludes that the

Pedestrian Comfort Level Categorisation is ‘A+,’ during both AM and PM peak

hour levels for Ascot Road, and during the PM peak for Croxley View, reducing

slightly to ‘A’ during the AM peak in this location on account of the number of

pedestrians.

3.31 These available pedestrian links therefore have capacity to accommodate

additional demand.

Public Transport - Bus

3.32 Whippendell Road and Watford Road act as important east-west bus corridors,

accommodating frequent services that provide access to Watford Town Centre

and surrounding settlements such as Hemel Hempstead, Garston, Watford

Town Centre, Maylands Business Park and Maple Cross and Chorleywood,

North Bushey, Rickmansworth and Harlow.


27

3.33 A number of these services continue into the Watford and Croxley business

parks via Ascot Road, including in particular W30, which provides a frequent

service during traditional commuting periods that links the site to Watford

town centre and Watford Junction.

3.34 A similar town centre service, route 10, can be accessed from the eastern

extent of Croxley View.

3.35 Table 3.3 below summarises the bus routes that are available from the site.

3.36 In terms of bus stop facilities, the closest bus stop to the site is a temporary

flag bus stop situated to the south of Ascot Road Old, approximately 170m

south west of the site, which is assumed to act as the terminal stop for services

accessing Morrisons. There are also northbound and southbound flag bus

stops located on Ascot Road New, which are within 300m of the site.

3.37 There are two flag bus stops located on Whippendell Road, with the

westbound and eastbound stops being approximately 280m and 420m from

the site respectively. Northbound and southbound bus stops on Watford Road

are within 620m of the site.


28

TABLE 3.2: BUS ROUTES

Bus Stop

Bus Routes

From To Key Destinations

Peak Time Service

Frequency

(Monday - Friday)

Daily Service Frequency

(Saturday - Sunday)

Old Ascot Road /

Ascot Road

R2 Watford – Clarendon

Road Chorleywood

Croxley, Rickmansworth, Berry Lane Estate,

Heronsgate, Chorleywood Two per day No service

W30 Watford -

Caxton Road

Croxley Green

Business Park

Watford Junction Station, Market Street, Watford Underground Station,

Watford General Hospital, Rickmansworth Road

Every 15 – 30 minutes

No Service

W18 Morrisons, Ascot Road

North Bushey Beechen Grove, North

Watford, North Bushey

One per hour between 9am-

4pm

Saturday - One per hour

between 9am-4pm

Whippendell

Road

320

Boxmoor Hemel

Hempstead Station

Berry Lane Estate

Hemel Hempstead Riverside, Bedmond High Street, Garston, Watford Junction Station, Watford

High Street, Rickmansworth Rail

Station

Every 10 – 20 minutes

Saturday - Every 15 – 20 minutes

Sunday – One per hour

324 Meriden Maple Cross

Garston, Watford High Street, Watford General Hospital, Croxley Green, Rickmansworth, Maple

Cross

2-4 per hour

Saturday – 2 per hour

Sunday – No Service

W1 Watford

High Street Maple Cross

Croxley Green, Vicarage Road, Croxley Green,

Rickmansworth, Maple Cross

One per day

Saturday - One day

Sunday – One per hour

Watford Road

41 Maple Cross

Garston

Rickmansworth, Croxley Green, Watford General

Hospital, Clarendon Road, North Watford, Abbots

Langley

One per day No service

336 High

Wycombe Watford

Town Centre

Wycombe Marsh, Amersham, Chorleywood, Rickmansworth, Croxley

Green

One per hour

Saturdays – One per hour

Sundays – No Services

951 Potters Bar Thorpe Park

South Mimms, Borehamwood, Bushey,

Watford High Street, Croxley Green,

Rickmansworth, Maple Cross, Staines

(Service from March to

December)

2 per day

Saturdays – 2 per day

Sundays – No Service

X336 High

Wycombe Watford

Town Centre

Wycombe Marsh, Amersham, Chorleywood, Rickmansworth, Croxley

Green

One per hour

Saturdays – One per hour

Sundays – No Services


29

Rail Accessibility

3.38 In terms of rail accessibility, Watford Station, which is the terminal London

Underground Metropolitan Line station, is located approximately 1.5km north

east of the site, providing frequent services toward central London.

3.39 This station will, however, close as a result of the opening of the Croxley Rail

Link, which will instead be supported by a new station immediately opposite

the development site, referred to as Cassiobridge Station, accommodating

Metropolitan Line services toward Watford High Street and Watford Junction.

3.40 On completion of the link, it is understood there will be 6 trains an hour during

peak periods and 4 for the rest of the day.

3.41 Watford Junction is a National Rail station, which provides ongoing travel

opportunities toward East Croydon, Tring, London Euston, St Albans Abbey,

Milton Keynes, Birmingham New Street and Liverpool Lime Street.

Local Highway Network

3.42 The site is bound to the west by Ascot Road Old, which currently operates one-

way southbound, with a contraflow cycle lane, and from which the existing

site is accessed.

3.43 Ascot Road Old runs parallel with the Ascot Road New, a dual-carriageway,

which provides access to the Watford Business Park and Croxley Green

Business Park.

3.44 Access to both Ascot Road New and Ascot Road Old to the north is taken from

two roundabout junctions with the A412 Rickmansworth Road and

Whippendell Road, which in turn provide access to Watford town centre

located approximately 2.5km to the east. Continuing east past the town

centre, the A412 links with the A4008, which connects to junction 5 of the M1,

approximately 6km to the east of the site.

3.45 The A412 Rickmansworth Road links with the A412 Watford Road which

travels west past Croxley Station through Croxley Green and Rickmansworth,

connecting with the M25 at Junction 17, approximately 7km to the west.


30

3.46 The Whippendell Road junction also includes a fourth arm, Raven Close, which

provides direct access to a residential estate.

3.47 To the south Ascot Road Old forms a priority junction with an access road that,

to the east, provides access to the Morrison’s Supermarket / Ascot Road

Community Free School and to the west forms a 4 arm roundabout junction

with Ascot Road New. The exit arm from this junction toward Ascot Road Old

is particularly wide, accommodating a right turn lane that acts as a waiting

area for servicing vehicles accessing a Morrisons goods yard.

3.48 West of this roundabout is another 4-arm roundabout, which provides access

to Blackmoor Lane, Hatters Lane and Greenhill Crescent.

3.49 In terms of vehicle movements, there is a distinct tidal profile, reflecting the

adjacent lands uses employment status, with vehicles entering the Ascot Road

area in the AM peak from both Watford Road, Rickmansworth Road and

Whippendell Road, and leaving in the PM peak.

3.50 Traffic impact analysis of this local highway network is included within

subsequent sections of this TA.

Controlled Parking Zones

3.51 The site is not currently located within an existing Controlled Parking Zone

(CPZ).

3.52 The closest CPZ to the site (zone T) operates along Whippendell Road, from

the junction with Ascot Road, encompassing Cassiobridge Road, Queen Mary’s

Road and Sydney Road, restricting on-street parking to permit holders only

Monday to Saturday between 08.00am and 18.30pm, with additional

restrictions in place on Watford Football Club match days.

3.53 Otherwise, there are residential areas that surround the site that are not

subject on on-street parking controls, including in particular the residential

estate accessed from Croxley View, south east of the site.


31

3.54 The extent of the CPZ is indicated on Figure 3.3, along with the rest of the

transport infrastructure described above.

Personal Injury Accident Data

3.55 Personal Injury Accident (PIA) data has been sourced from HCC for a period of

5 years from 2011 to 2016, encompassing the local highway network

surrounding the site.

3.56 The data, which is attached as Appendix I, provides details of PIA’s reported

to the police. It does not include, therefore, damage only incidents or near

misses.

3.57 Over the study period, there were a total of 18 incidents, with 17 classified as

slight and 1 classified as serious, with no fatalities.

3.58 The majority of the PIAs involved just vehicle collisions, however 9 included

vulnerable road users, with 3 involving pedestrians and 6 involving cyclists.

3.59 Of those incidents involving pedestrians, 2 occurred at the Ascot Road toucan

crossing south of the Whippendell Road junction, with vehicles failing to stop

at a red signal and colliding with pedestrians on the crossing.

3.60 Of the incidents involving cyclists, the significant majority involved vehicles

failing to see cyclists circulating on a roundabout and pulling out into their

path.

3.61 A number of the vehicular only movements involved shunts at roundabouts,

with trailing vehicles anticipating a vehicle to enter a junction when they did

not.

3.62 Overall however, there does not appear to be a geographical clustering of

incidents which might suggest some fault of the local highway network.

Car Club


32

3.63 A review of established car club operators has established that there are no

car clubs within close proximity of the site.

Summary

3.64 In summary therefore, the subject site benefits from being located within a

highly accessible location, both in terms of proximity to alternative modes of

travel and essential social infrastructure, including employment, retail and

education land uses.

3.65 This accessibility will only improve in the future, with the introduction of

Cassiobridge Station adjacent to the site, forming part of the Metropolitan

line, with services to Watford town centre and Central London.

3.66 Residents of the site will not, therefore, be reliant on travel by car to travel

to/from the site, which has in turn influenced the adopted car parking

strategy.

3.67 The site also benefits from an established pedestrian and cycle network,

allowing residents to adopt the most sustainable forms of travel to access land

uses within close proximity, including Watford town centre.


33

4.0 DEVELOPMENT PROPOSALS

Scale of Development and Proposed Site Layout

4.1 The development proposals are to demolish the existing buildings, remove the

existing points of access, and introduce a residential led development proposal,

with 4 blocks accommodating a total of485 units, with a mix of unit types and

tenure as summarised in Table 4.1 below.

TABLE 4.1: ACCOMMODATION SCHEDULE

Unit Size Private Tenure Social Tenure Total

1 Bed 182 70 252

2 Bed 123 85 208

3 Bed + Duplex 10 15 25

Total 315 170 485

4.2 The proposed site layout is attached as Appendix C.

4.3 The proposed buildings are set back from the Ascot Road Old frontage so as not

to preclude any of the proposals associated with the Cassiobridge Station in

relation to the introduction of a shared use footway/cycleway.

4.4 The proposed buildings are also set back from the railway viaduct to the north,

allowing the introduction of a footway link along the northern edge of the site,

providing a direct link toward the station.

4.5 The blocks are set around a central communal area of soft and hard landscaping,

part of which will act as a shared surface to allow essential vehicle access, such as

oversized deliveries and emergency vehicles.

4.6 The development proposals also include an element of commercial floorspace,

accommodated within three small units at the ground floor of Blocks A and B, with

a total GFA of 1,093sqm, but with no allocated car parking. It is intended that two


34

of the units will be promoted as offering flexible retail space, with the remaining

unit operating as a community centre. The commercial units will therefore

provide a service directed at the immediate site residents.

Pedestrian Access

4.7 Pedestrian access into the site will be from the Ascot Road Old frontage,

connecting with the existing footway provision, with a series of pedestrian links

across the layout that provides access to each building core, including a

pedestrian link along the northern edge of the site that will provide a focal point

for movements to/from the station.

4.8 If necessary, a signalised pedestrian crossing facility could be introduced in this

location, which is indicated on drawing number 16037-200, providing a safe point

of access between the site and the station.

Vehicle Access

4.9 The development proposals promote the introduction of a vehicular access in the

site’s south west corner, which will provide access to the undercroft parking area,

operating as a left-in / left-out. The access is staggered away from the

Cassiobridge station commuter car park access.

4.10 Vehicle swept path analysis of conflicting large car movements using this access

is provided at drawing 16037-201.

4.11 In addition, the pedestrian access route along the site’s northern frontage, will

also act as a shared surface, being a minimum of 3.7m wide, allowing for

infrequent access for emergency vehicles and oversized delivery vehicles.

4.12 Vehicle swept path analysis indicating these movements is provided at drawing

16037-202/203, demonstrating that a fire tender would be able to get within 18m

of a dry/wet riser position for each block, without having to adopt an excessive

reverse distance.

4.13 A centrally located turning head will allow these design vehicles to enter and exit

the site within forward gear, with there being sufficient hardstanding infront of

the most north/eastern blocks to undertaken such a movement. However, for the


35

purpose of delivery and servicing this will be limited to 7.5T Box Vans as

accommodating larger vehicles would result in a significant loss to the internal

soft landscaping, with oversized delivery and service vehicles addressed below.

Whilst these oversized vehicles can access the site, they will require an escorted

reverse movement back onto Ascot Road, which is deemed acceptable given they

are likely to be infrequent in nature, escorted by a member of the on-site

concierge team in order to manage any potential pedestrian conflicts.

Delivery and Service Vehicle Access

4.14 Day-to-day deliveries, encompassing post, supermarket home deliveries, couriers

etc. are otherwise envisaged to occur using dedicated loading bays along the

Ascot Road Old frontage, with a concierge services located within Block A able to

take receipt of such deliveries and/or direct them to a particular block on foot.

4.15 The Ascot Road Old footway/cycleway proposed as part of the Cassiobridge

Station scheme will divert to the back of the layby, with the necessary land

transfers made to ensure these facilities are accommodated within public

highway where they encroach into the site boundary.

4.16 In terms of refuse collections, it is envisaged that a management arrangement will

be implemented where, on collection day, bins are brought from their undercroft

storage areas to a temporary holding area in the south-west corner of the site,

with an additional layby provided to allow refuse vehicles to get within 10m of

this holding area, with this strategy indicated on drawing number 16037-204.

Car Parking

4.17 The development proposals include an undercroft car park, accommodating

approximately 185 car parking spaces, reflecting a parking ratio of 0.38 spaces per

unit.

4.18 The car park includes a number of blue badge spaces and will include three of

spaces that benefit from electric vehicle charging points.

4.19 In terms of compliance with adopted local planning policy, relevant car parking

policies and standards are those set out within saved policies of WBC’s District

Plan.


36

4.20 Policy T22 Car Parking Standards, identifies that development proposals need to

comply with maximum parking standards, which are based on a method of zonal

restraint, dependent on the accessibility of the site.

4.21 The current adopted zonal map identifies the site as being located within zone 4,

of 4, the least accessible, meaning no parking restraint factors are applied.

However, this does not take into account the committed introduction of a London

Underground station adjacent to the site, which will result in a step change in site

accessibility and nor has it taken into account the recent introduction of a large

food retail unit and primary school.

4.22 It is therefore necessary to consider a manual assessment of the site’s

accessibility, which, according to Appendix 2 of WBC’s Local Plan Saved Policies,

is based on a point scoring system related to the following:

Proximity to shopping centres and retail facilities

Economic health of Watford

Public transport accessibility

Pedestrian and cycling routes.

4.23 With regards to proximity to shopping facilities, scores are achieved based on the

accessibility of a site to the retail core, scoring a maximum of 3 points if within

300m. Sites that contained local shopping facilities were then given a score of 2.

On this basis, we consider the site as scoring 2.

4.24 With regards to economic health, the retail core was given a maximum score of

4. On this basis, reflecting the allocation of the site within a wider masterplan

adjacent to a major employment area, we consider the site as scoring 3.

4.25 With regards to public transport accessibility, a site must be within 400m walking

distance of a bus route and 800m of a railway station, with higher scores based

on the service frequency and infrastructure quality. The maximum score available

was 6, which included a select number of sites around Watford Junction. On this

basis, we consider the site as scoring 4.


37

4.26 With regards to pedestrian/cycle accessibility scores were for a range of 0-2. On

this basis, we consider the site as scoring 1.

4.27 The total score for the site would therefore be 10, meaning it is in Zone 2.

4.28 Maximum residential parking standards for a site in Zone 2 are as follows:

1/2 bed units – 1 space per dwelling

3 bed units – 1.5 spaces per dwelling

4.29 Based on these standards and the proposed accommodation mix, the

development proposal would be permitted to provide a total of 498 parking

spaces. The proposed provision of 185 spaces therefore represents 37% of the

maximum standards.

4.30 Whilst these standards represent the adopted policy position, emerging car

parking policy requirements are set out in the Core Strategy Part 2 Development

management documents. Emerging policy T6 Car Parking Provision states that car

parking should be provided in accordance with standards that are based on the

accessibility of a site. For the most accessible sites (Zone 1), which we believe the

site is located within once Cassiobridge Station is operational, the following

parking standards are relevant:

1/2 bed units – 0.75 space per dwelling

3 bed units – 1 spaces per dwelling

4.31 Based on these standards and the proposed accommodation mix, the

development proposal be permitted to provide a total of 370 parking spaces. The

proposed provision of 186 spaces therefore represents 50% of the standards.

4.32 However, adopted policy Policy T24 Residential Development, states that

‘planning permission will only be granted for residential use where the full parking

needs generated can be met on site, and of the public highway unless the site is in

a suitable Town Centre site or other location with good access to passenger

transport.’ Furthermore, Policy T26 Car Free Residential Development, states that,

‘car free residential development will be considered in suitable locations which are


38

highly accessible by passenger transport, close to amenities and services, subject

to the provision of satisfactory site covenants, on-street parking controls and

measures to control displaced parking in adjacent areas.’

4.33 In addition, the supporting narrative to emerging policy T6 state that ‘flexibility

on the recommended standards to allow ‘car lite’ development in the proximity of

large scale public transport infrastructure where secure cycle storage is provided

will be considered.’ The narrative continues and states, ‘Where car parking

provision does not adhere to the suggested guidance, provision of dedicated car

club spaces and vehicles and secure cycle storage is recommended. Provision for

car clubs will be expected for residential development in Special Policy Areas

where more than 20 parking spaces are proposed.’

4.34 There is, therefore, adopted and emerging policy justification for parking

provision below the identified standards where a package of measures are

introduced relating to increased cycle parking and car club provision. This has

been embraced by the development proposal, with the introduction of cycle

parking provision in excess of the residential standards and the introduction of 2

car club spaces, supported by an Applicant funded marketing package to

encourage update amongst residents.

4.35 It is acknowledged, however, that there are a lack of parking controls in operation

within some residential areas surrounding the site, potentially allowing parking

overspill to occur from the site, with the adopted policy in relation to car free

developments requiring such a restriction to be in place.

4.36 However, the same residential areas are already under a similar threat after the

introduction of Cassiobridge Station, with commuters likely to want to avoid

paying car parking charges within the associated car park and displacing away

from the station.

4.37 The introduction of a CPZ within the uncontrolled residential areas is something,

therefore, that existing residents may be supportive of and the Applicant will

accept any restriction that prevents residents from applying for parking permits

within the CPZ. To this end, the Applicant would be willing to provide a

proportional contribution to WDC in order to facilitate any public consultation


39

and/or designs/implementation of a CPZ within those areas under potential

overspill pressures.

Car Club

4.38 In order to mitigate the restricted car parking provision, the development

proposals promote the introduction of a lay-by along the Ascot Road Old frontage

that will be used to accommodate two parking spaces for use as a car club,

indicated on drawing number 16-037-205.

4.39 Discussions have been initiated with a leading car club operator, details of which

are provided at Appendix J, which has confirmed that to subject to financial

support from the Applicant they would be willing to operate a car club in this

location. The financial support would take the form of household memberships

and driving credit, to incentivise future residents to join.

4.40 The car club would be open to residents of both the subject site and adjacent sites

that form part of the Ascot Road masterplan.

Cycle Parking

4.41 The development proposals include cycle parking spaces within the undercroft

parking area, which are therefore by definition sheltered.

4.42 The cycle parking is located within rooms adjacent to each core that only residents

will have access to and is therefore by definition secure.

4.43 A total of 575 cycle parking spaces are provided, a proportion of which can be

made available to employees of the proposed commercial floor space, leaving a

residual number for the resident that exceeds WBC’s adopted standards of 1

space per unit.

4.44 Additional visitor cycle parking provision will be included at ground floor.

Sustainable Transport Strategy

4.45 The development proposals will be supported by a TP, which will promote a

sustainable transport strategy.


40

4.46 The Travel Plan will include a number of management strategies and measures to

promote and support sustainable travel, including:

Car Club provision and incentive package

Car Share database

Car parking management plan

Controlled Parking Zone permit exemption

Bicycle parking provision

Bicycle User Group

Bicycle maintenance equipment

Travel Options Leaflet

Site Maps

4.47 The TP will be supported by a monitoring and reporting strategy, with a Travel

Plan coordinator appointed to manage the strategy on a day to day part time

basis.

Construction

4.48 The Applicant will accept a conditional requirement for a Construction Method

Statement to be produced for approval prior to works on site.

4.49 Initial details relating to construction are however provided within the relevant

ES chapter. This identifies that the construction programme is envisaged to take

30 months, involving site set up, demolition, construction, fit out and landscaping.

4.50 With regards to vehicle access, it is envisaged that vehicles will enter and exit the

site via Ascot Road, with banksmen employed to ensure no pedestrian conflict

and no build-up of traffic on Ascot Road.

4.51 Vehicles will route to the site via the most strategic routes possible, including

Watford Road and Rickmansworth Road, avoiding less strategic roads such as

Whippendell Road.

4.52 Vehicle movements to/from the site will be managed to avoid peak periods as far

as possible and a number of measures will be employed on site to mitigate their

impact, including noise and dust suppression, wheel-wash facilities etc.


41

4.53 Construction personal will also be encouraged to access the site via the most

sustainable modes of travel possible, with contractors often employing a form of

communal transport to take employees between the site and public transport

infrastructure.

4.54 It is estimated that during peak periods of demolition, there will be 60 HGVs

accessing the site on a daily basis.

4.55 It is estimated that during peak periods of construction, there will be 40 HGVs

accessing the site on a daily basis.


42

5.0 TRIP GENERATION AND DISTRIBUTION

Introduction

5.1 The TASR identified the intended methodology for quantifying the anticipated

multimodal trip generation and distribution profile associated with the proposed

scale of development.

5.2 The TASR confirmed that the proposed commercial land uses are envisaged to

accommodate demands generated by the proposed development and would not,

therefore, generate any external trips that would place undue pressure on the

local highway network. Trip generation calculations have not, therefore, been

undertaken for the proposed commercial land uses.

5.3 This section of the TA therefore reproduces the proposed methodology, as set out

within the TASR, to quantify multimodal trip generation associated with the

proposed residential units.

5.4 Subsequent pre-application correspondence with HCC confirmed that this

methodology has been accepted.

Total and Vehicular Trip Generation

5.5 In order to estimate the likely total and vehicle trip generation for the proposed

scale of development, the industry standard TRICS database has been relied upon.

5.6 A representative site selection criteria was adopted based on the following

characteristics:

o Town Centre or Edge of Town Centre Locations;

o Located within England, including Greater London, but with

central/inner London sites manually deselected; and

o Bedroom ratio of at least 1.5 spaces per unit.

5.7 Separate trip rates were then established based on the tenure of each flat,

adopting the ‘flats privately owned’ and ‘local authority/affordable flats’ sub land

uses within the TRICS database.


43

5.8 A total of 12 sites fulfilled this selection criteria for the private flats (incorrectly

referred to as 11 within the TASR) and 3 for the affordable flats, from which the

total ‘all person’ trip generation rates could be established, with full details

provided as Appendix K and L.

5.9 For the private flats, off the 12 selected, only 2 were located within Greater

London, each of which was located in outer London, with site references below.

HO-03-C-02 – Brentford, Hounslow

KI-03-C-02 – Kingston Upon Thames, Kingston

5.10 A review of the rank order list for the selected sites demonstrated that the two

sites did not display anomalous trip rates when compared with the others and

therefore their inclusion is warranted.

5.11 In order to generate vehicular trip rates, a further site selection criterion was

attached, with sites included that have less than 1 parking space per unit. This

resulted in the private site list reducing to 5 sites, with the affordable list

remaining the same. Of the reduced private sites list, only the Hounslow Greater

London site was retained and again this did not generate anomalous vehicular trip

rates when compared with the other retained sites.

5.12 The subsequent all person and vehicular trip rates are identified below in Table

5.1, which have been applied to the proposed scale of development.


44

TABLE 5.1: TRIP RATES AND PREDICTED TRIP GENERATION

Vehicle All Person

AM Peak PM Peak Daily AM Peak PM Peak Daily

IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL

Private

Tenure 315

Units

Trip Rate

Per Unit 0.038 0.081 0.119 0.078 0.059 0.137 0.609 0.637 1.246 0.087 0.442 0.529 0.472 0.233 0.705 2.43 2.626 5.056

Trips 12 26 37 25 19 43 192 201 392 27 139 167 149 73 222 765 827 1593

Affordable

Tenure 170

Units

Trip Rate

Per Unit 0.035 0.078 0.113 0.024 0.049 0.073 0.447 0.507 0.954 0.245 0.795 1.04 0.706 0.304 1.01 4.546 4.369 8.915

Trips 6 13 19 4 8 12 76 86 162 42 135 177 120 52 172 773 743 1516

Total 485 Trips 18 39 57 29 27 55 268 287 555 69 274 343 269 125 394 1538 1570 3108


45

5.13 Table 5.1 demonstrates therefore that the scale of development is anticipated to

generate 57 vehicle trips in the AM peak, 56 in the PM peak and 555 across the

day.

5.14 Table 5.1 demonstrates therefore that the scale of development is anticipated to

generate 343 all person trips in the AM peak, 394 in the PM peak and 3108 across

the day.

5.15 Table 5.2 below then identifies the net traffic impact, by subtracting the observed

vehicle movements generated by the existing occupant, detailed in Table 3.1,

from the predicated traffic generated associated with the proposed scale of

development, detailed in Table 5.1.

TABLE 5.2: NET TRAFFIC IMPACT

AM Peak PM Peak Daily

IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL

Existing 7 1 8 4 12 16 70 81 151

Proposed 18 39 57 29 27 56 268 287 555

Net

Impact 12 38 49 25 15 40 198 206 404

5.16 Table 5.2 therefore indicates that the development proposals are anticipated to

generate a net traffic impact totalling 49 vehicle movements in the AM peak, 40

in the PM peak and 404 across the day.

Vehicle Trip Distribution

5.17 Vehicular trip distribution has been quantified using 2011 Census data Table

WU03EW, which details the ‘location of usual residence and place of work by

method of travel to work,’ at middle super output area, with ward level data being

unavailable for this dataset. The distribution profile for this journey purpose is

assumed to be representative of all journey purposes.


46

5.18 The site’s middle super output area reference, E02004978 Watford 011, is

adopted as the trip origin, with all trip destinations taken at local authority level

and middle super output area for trips with a destination within WBC itself.

5.19 Desktop mapping software is then used to assign these trips to the local highway

network.

5.20 The resultant distribution profile is indicated on Figure 5.1, with Figures 5.2 and

5.3 indicating the AM and PM peak development traffic distribution respectively.

Full analysis is provided at Appendix M, with a summary distribution profile

provided below at Table 5.4.

TABLE 5.4: DISTRIBUTION PROFILE

Route Reference Route Description Proportion

1 Site Access, Ascot Road Old, Ascot Road

New, A412 Rickmansworth Road East

43%


New, A412 Rickmansworth Road West

28%


New, A412 Rickmansworth Road West,

Baldwins Lane

9%


New, Whippendell Road

18%

5 Internal – Site Access, Ascot Road Old,

Ascot Road south

2%

Total 100%

5.21 From Table 5.4, it can be seen that the majority of traffic (43%) is distributed east

to/from the A412 Rickmansworth Road, and therefore toward/from central

Watford.

5.22 A smaller proportion (37%) is distributed to/from the west via either Baldwins

Lane or the A412 Rickmansworth Road.

5.23 Finally, a smaller proportion (18%) is distributed via Whippendell Road.


47

Multimodal Trip Generation

5.24 In terms of multimodal trip generation, the vehicle trip generation proportions

have been subtracted from the all person total trip generation, detailed in Table

5.1, to establish the non-vehicular trip generation, detailed below in Table 5.5.

TABLE 5.5: PREDICTED NON-VEHICULAR TRIP GENERATION

Non-Vehicle Trip Rate



Private

Tenure

315 Units

Trip

Rate

Per Unit

0.049 0.361 0.41 0.394 0.174 0.568 1.821 1.989 3.81

Trips 15 114 129 124 55 179 574 627 1200

Affordable

Tenure

170 Units

Trip

Rate

Per Unit

0.21 0.717 0.927 0.682 0.255 0.937 4.099 3.862 7.961

Trips 36 122 158 116 43 159 697 657 1353

Total Trips 51 236 287 240 98 338 1270 1283 2554

5.25 These non-vehicular trips have then been proportioned to individual modes of

travel using 2011 Census ‘method of journey to work’ proportions, which is

considered to be a reasonable proxy for all journey purposes.

5.26 Whilst the site is located within the Holywell ward, to account for the fact that at

the time of the 2011 Census this ward did not accommodate a station, a number

of wards across Watford have been considered to quantify the multimodal

proportions. These include wards that accommodate a station, including the

Metropolitan Line, such as Vicarage and Central. This information is summarised

below as Table 5.6.


48

TABLE 5.6: 2011 CENSUS METHOD OF TRAVEL TO WORK DATA

Mode Holywell (no

station)

Park Ward

(station)

Vicarage

(no station)

Central

(station)

Oxhey

(station) Watford LA

Underground,

Metro, Light

Rail, Tram

8% 12% 7% 6% 5% 5%

Train 5% 9% 8% 18% 20% 11%

Bus, Minibus or

Coach 5% 2% 7% 8% 3% 5%

Taxi 0% 0% 1% 0% 1% 0%

Motorcycle,

Scooter or

Moped

1% 1% 1% 1% 1% 1%

Driving a Car or

Van 52% 58% 42% 38% 55% 56%

Passenger in a

Car or Van 4% 3% 3% 2% 3% 4%

Bicycle 3% 3% 4% 3% 2% 2%

On Foot 22% 10% 27% 23% 9% 14%

Other 1% 0% 1% 1% 1% 1%

5.27 From Table 5.6 therefore, it is apparent that those wards with a station within

their boundary have a higher proportion of trips undertaken by

underground/rail, resulting in a lower proportion of trips undertaken by car,

with the most central wards (Central, Vicarage and Holywell) demonstrating a

reasonable proportion of trips on foot.

5.28 It is anticipated therefore that the travel patterns of residents to the site is

likely to reflect both Holywell and the more central wards following the

introduction of Cassiobridge Station. The Central ward demonstrates a much

lower reliance on car and so this will be discounted from the analysis. The

Oxhey site generates a high reliance on travel by Train, likely due to Bushey

station being located within the ward. However, the London Underground

reliance is lower than the other wards, due to there being no such station

within the ward boundary.


49

5.27 Table 5.7 then takes an average modal split from each of the selected wards,

excluding Central, to quantify the modal splits.

TABLE 5.7: MODAL SPLIT PROPORTIONS (AVERAGE OF HOLYWELL, PARK, VICARAGE AND OXHEY WARDS)

Mode of Travel Proportion

Underground, Metro, Light Rail, Tram 17%

Train 22%

Bus, Minibus or Coach 9%

Taxi 1%

Motorcycle, Scooter or Moped 1%

Passenger in a Car or Van 7%

Bicycle 6%

On Foot 36%

Other 1%

Total 100%

5.28 Table 5.7 therefore details a high proportion of trips by public transport and on

foot, reflecting the ward locations proximity to the town centre and employment

locations such as the adjacent business parks. Table 5.7 demonstrates a higher

reliance on Train travel than London Underground travel, likely due to the

influence of Oxhey ward, within which is Bushey Station. In reality, based on the

proximity of Cassiobridge London Underground Station, the site is likely to

generate a higher reliance on travel by this mode than Train, but within the total

public transport proportions quantified.

5.29 Table 5.8 then applies these modal split proportions to the total non-vehicle trips

to quantify the total non-vehicular trips, with focus given to public transport,

pedestrian and cycle trips.


50

TABLE 5.8: MULTI-MODAL TRIP GENERATION

Non-Vehicle Trips



Underground,

Metro, Light

Rail, Tram

Private

Tenure

315 Units 3 19 22 21 9 30 98 107 204

Affordable

Tenure

170 Units 6 21 27 20 7 27 118 112 230

Total 9 40 49 41 17 57 216 218 434

Train

Private

Tenure

315 Units 3 25 28 27 12 39 125 136 261

Affordable

Tenure

170 Units 8 27 34 25 9 35 152 143 295

Total 11 51 62 52 21 74 277 279 556

Bus, Minibus

or Coach

Private

Tenure

315 Units 1 10 12 11 5 16 52 57 108

Affordable

Tenure

170 Units 3 11 14 10 4 14 63 59 122

Total 5 21 26 22 9 31 115 116 231

Bicycle

Private

Tenure

315 Units 1 7 7 7 3 10 33 36 69

Affordable

Tenure

170 Units 2 7 9 7 2 9 40 38 78

Total 3 14 16 14 6 19 73 74 147

On Foot

Private

Tenure

315 Units 5 40 46 44 19 64 204 223 427

Affordable

Tenure

170 Units 13 43 56 41 15 57 248 233 481

Total 18 84 102 85 35 120 451 456 907

5.30 Reflecting the 2011 Census proportions, Table 5.8 indicates a high reliance on

public transport infrastructure, particularly in terms of rail and underground trips,

with a smaller reliance on local bus services. Table 5.8 also indicates a high


51

reliance on direct pedestrian trips, with a smaller reliance on cycle trips, a

proportion that the accompanying TP will seek to increase.

Multimodal Trip Distribution

5.31 In terms of distribution of these trips, it is anticipated that the significant majority

of direct pedestrian trips and cycle trips will be distributed south, toward the

existing employment centres and schools, or via the Croxley View link toward

Watford town centre, with a proportion also distributed north via Whippendell

Road.

5.32 In terms of rail/Underground trips, it is anticipated that these will all be

distributed toward the new Cassiobridge station, toward central London or

Watford Junction.

5.33 In terms of bus trips, a review of 2011 Census data details that, for local

authorities or Watford MSOA’s with a proportion greater than 5%, the significant

majority of bus trips from this location are distributed to or via Watford town

centre with onward trips to Hertsmere (63%) with a reasonable proportion also

distributed toward TRDC (37%).


52

6.0 TRAFFIC IMPACT

Introduction

6.1 This section of the TA, undertakes a traffic impact analysis, presenting the results

of junction capacity assessments at a number of off-site junctions for a range of

different scenarios.

6.2 The section begins by describing the study area and scenarios that have been

tested, before providing a summary of the modelling results on a junction by

junction basis so that the different scenarios can be considered side by side.

6.3 The section also includes an assessment where the adjacent Cassiobridge Station

has not been delivered.

Study Area

6.4 The study area reflects that which was adopted within the TA produced in support

of the Buildings 1 and 2, Marlins Meadow site within TRDC, encompassing the

following junctions:

Ascot Road Old / Ascot Road New roundabout junction

Ascot Road Old / Ascot Road New / Whippendell Road roundabout

junction

Ascot Road New / A412 Rickmansworth Road roundabout junction

A412 Rickmansworth Road / Watford Road / Baldwins Lane

roundabout junction

6.5 The study area also includes the Ascot Road Old priority junction with the Ascot

Road Community Free School / Morrison’s access road.

Scenarios

6.6 The junction capacity assessments have been undertaken for a number of

different scenarios in order to attribute the cumulative impact to different phases

of development.

6.7 These scenarios are summarises as follows:


53

2016 existing year, informed by 2015 traffic counts undertaken in support of

TRDC application reference 15/1427/FUL, Buildings 1 and 2, Marlins Meadow

2021 future year baseline, encompassing committed development

2021 future year baseline (as above) plus development proposal

2021 future year baseline plus selected sites within the Ascot Road

Masterplan

2021 future year baseline plus Ascot Road Masterplan (as above) plus

development


Woodshots Meadow High Tech Site


Woodshots Meadow High Tech Site (as above) plus development

2016 Existing Year

6.8 For this scenario, turning movements across the study area have been based on

the TA that was submitted in support of TRDC application reference 15/1427/FUL,

Buildings 1 and 2, Marlins Meadow, which was informed by turning counts

undertaken in 2015, which are reproduced as Figures 6.1 and 6.2.

6.9 In order to generate the 2016 traffic flows, TEMPRO (Version 7) growth factors

for the MSOA in which the site is located have been applied to the observed 2015

movements, detailed below as Table 6.1.

TABLE 6.1: 2015-2016 TEMPRO GROWTH FACTOR

AM Peak PM Peak

1.021 1.020

6.10 The resultant 2016 traffic flows are indicated on Figures 6.3 and 6.4.

6.11 For the Ascot Road Old / Morrisons access road junction however, a 2016 turning

count has been undertaken to inform this TA, as no such turning count data was

included within the 2015 assessment. Growth factors have not, therefore, been

applied to this priority junction. The turning counts for this junction are attached

as Appendix N.



54

2021 Future Year Baseline Encompassing Committed

Development

6.13 Again, the TEMPRO database has been used to generate 2016-2021 growth rates.

6.14 Two growth rates have however been sourced, with a rate at MSOA level sourced

and applied to all of the turning movements travelling to/from the business parks

via Ascot Road, and at local authority (WBC) level for through movements that

don’t access the business parks i.e. the east/west movements between

Rickmansworth Road, Watford Road and Whippendell Road.

6.15 In addition, to avoid double counting and account for the fact that much of the

assumed growth within the TEMPRO database for this location is in fact

accommodated within the Ascot Road masterplan, the alternative assumption

function has been used, to manually change the assumed number of future

households and jobs.

6.16 The TEMPRO database assumes an increase in households and jobs between

2016-2021 for the whole of Watford and the relevant MSOA as summarised below

in Table 6.2

TABLE 6.2: TEMPRO ASSUMED DEVELOPMENT

Geography Household/Jobs 2016 2021 Change

Watford

Households 39017 40665 1648

Jobs 59623 61609 1986

MSOA

Households 3683 3838 155

Jobs 6258 6402 144

6.17 For the relevant MSOA therefore, the TEMPRO assumed increase in households

and jobs is significantly less than the envisaged scale of development

accommodated within the Ascot Road masterplan and/or that which is

committed. The alternative assumption has therefore been adopted that there is

no additional households or jobs at the MSOA level, with this additional demand

instead included within specific committed developments, described below.


55

6.18 For the WBC level growth rates, the 2021 jobs has been reduced by 477 , based

on an assumed employee ratio of 1 per 13sqm for the masterplan site PS6, which

promotes the introduction of 6,200sqm of office floor space. Households have

then been reduced by 783 units, which is the sum of the site and residential

properties within the masterplan sites S2 (100) S3a (125) and PS5 (35) and PS7

(40).

6.19 Tables 6.3 then indicates the alternative TEMPRO growth rates that have been

adopted.

TABLE 6.3: 2016-2021 TEMPRO GROWTH FACTOR ALTERNATIVE ASSUMPTIONS

AM Peak PM Peak

Watford 1.049 1.048

MSOA 1.014 1.013


6.21 In terms of traffic flows associated with the committed developments, these have

been sourced from the TA’s that were submitted in support of each planning

application.

6.22 For the Cassiobridge Station development traffic flows however, the TA did not

explicitly detail the associated trip generation and nor did it include any traffic

flow diagrams. Instead, the Do Something ARCADY outputs have been compared

with the Do Nothing outputs to interpolate the development traffic that is assed

to the network. Similarly, as this was only available for two of the junctions within

the study area, the flows have been distributed based on observed turning

movement proportions, indicated on Figures 6.7 and 6.8. From these figures, it is

evident that the TA concluded that there would be a reduction in certain turning

movements as a result of the introduction of the station.

6.23 For the Ascot Road Community Free School committed development, it is

understood that at the time of the 2015 surveys, the school was only occupied by

60 pupils. The TA that was undertaken in support of the school based trip

generation on a total development of 420 pupils and 30 nursery places. Additional


56

committed school trips are therefore calculated on the basis of 320 primary

school pupils and 30 nursery spaces, with turning movements on the wider

highway network distributed based on observed turning movements and

indicated on Figures 6.9 and 6.10.

6.24 For the Buildings 1 and 2, Marlins Meadow committed development, the flows

have been sourced direct from the TA, indicated on Figures 6.11 and 6.12.

6.25 These committed development flows have been totalled and added to the 2021

flows, to indicate the future year baseline flows, indicated on Figures 6.13 and

6.14.

2021 Future Year Baseline Plus Development

6.26 To inform the 2021 Future Year Baseline Plus Development scenario, the net

increase in development trips has been calculated, by subtracting the existing

traffic flows from the proposed traffic flows.

6.27 These flows have then been added to the Future Year Baseline flows to generate

the 2021 Future Year Baseline Plus Development flows, indicated as Figures 6.15

and 6.16.

2021 Future Year Baseline Plus Ascot Road Masterplan

6.28 The following sites identified within the Ascot Road masterplan, along with their

assumed scale of development, have been included to inform this scenario, as

specified by HCC in response to the TASR.

S2 – 100 residential units

S3a – 125 residential units

P5 – 35 residential units

P6 – 6,200sqm B1a office space

P7 – 40 residential units

6.29 The residential trip rates and distribution profile adopted for the subject site have

been applied to the Masterplan residential sites, with assumptions made

regarding the likely point of access for sites off Ascot Road. For the P6


57

employment site, these trips have been distributed based on the same

distribution profile as the Buildings 1 and 2 Marlins Meadow site.

6.30 Relevant traffic flows for each of the masterplan sites are indicated as Figures 6.17

to 6.26, totalled in Figures 6.27 to 6.28, with the 2021 Future Year Baseline Plus

Masterplan flows indicated as Figures 6.29 and 6.30.

6.31 Whilst a number of other sites are identified within the Ascot Road Masterplan,

these have been rejected on the basis they will not have a direct vehicular

connection with the Ascot Road road network, being accessed from Croxley View,

e.g. S3b/S3c, and/or are currently operating with commercial success, meaning

they are unlikely to be available for redevelopment for a number of years, e.g.

PS2/PS3.

2021 Future Year Baseline Plus Ascot Road Masterplan Plus

Development

6.32 The development flows indicated in Figures 5.2 and 5.3 have been added to the

2021 Future Year Baseline Plus Masterplan flows indicated as Figures 6.29 and

6.30, with total flows indicated as Figures 6.31 and 6.32.


Woodshots Meadow High Tech Site

6.33 As part of the pre-application discussions, MA have been encouraged to engage

with the transport consultant that is preparing a TA in support of an emerging

development proposal for a site within the Croxley Business Park referred to as

the High-Tech site, in order to share trip generation and distribution data.

6.34 The proposals for this site see the introduction of a significant scale of office floor

space of approximately 40,000sqm GEA, and associated car parking totalling

approximately 1000 spaces, that will result in a net increase in vehicle movements

detailed below as Table 6.4.


58

TABLE 6.4: HIGH TECH SITE NET TRAFFIC IMPACT

AM Peak PM Peak

IN OUT TOTAL IN OUT TOTAL

Existing 141 12 153 15 57 72

Proposed 447 40 487 26 346 372

Net

Impact 306 28 334 11 289 300

6.35 Table 6.4 therefore reveals that the High Tech proposals will result in a significant

increase in vehicular trip generation.

6.36 Traffic flow information for the development has been supplied by the consultant

supporting that proposal, which is indicated as Figures 6.33 and 6.34.

6.37 These have been summated to the 2021 Future Year Baseline Plus Masterplan

flows, with the 2021 Future Year Baseline Plus Masterplan flows plus High tech

site flows indicated on Figures 6.35 and 6.36.


Woodshots Meadow High Tech Site Plus Development

6.38 The subject site development flows have then been added to the above scenario,

with the 2021 Future Year Baseline Plus Masterplan flows plus High tech site flows

indicated on Figures 6.37 and 6.38.

Capacity Assessments

6.39 Capacity assessments of each of the off-site junctions have then been undertaken

for each of these scenarios.

6.40 The industry standard software for modelling roundabouts, ARCADY, has been

used to create junction models of each of the off-site roundabouts, with

geometric parameters taken from the TA that was submitted in support of the

Buildings 1/2 Marlins Meadow planning application. For the Ascot Road Old

junction with the Morrisons access road, the industry standard software for

modelling priority junctions, PICADY, has been used, with geometric parameters

taken from OS mapping.


59

6.41 Tables 6.5-6.11 below presents the results of the analysis for each junction,

allowing each scenario to be compared side by side.

6.42 The results are presented in terms of ratio of flow to capacity (RFC) and queue

length (Q). A ratio of flow to capacity in excess of 0.85 indicates the junction is

operating above its practical capacity.

6.43 Full model outputs are provided as Appendix O.


60

TABLE 6.5: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / HATTERS LANE / GREENHILL CRESCENT /BLACKMOOR LANE ROUNDABOUT

Scenario 2016 2021 + Committed

Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development

Time Period AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak

Arm RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q

Ascot

Road 0.61 1.6 0.16 0.2 0.64 1.8 0.17 0.2 0.73 2.8 0.17 0.2 0.74 2.8 0.17 0.2 0.74 2.8 0.18 0.2 0.87 6.5 0.18 0.2 0.87 6.5 0.18 0.2

Greenhill

Crescent 0.22 0.3 0.4 0.7 0.22 0.3 0.4 0.7 0.26 0.4 0.41 0.7 0.28 0.4 0.42 0.7 0.28 0.4 0.42 0.7 0.37 0.6 0.42 0.7 0.36 0.6 0.42 0.7

Hatters

Lane 0.05 0.1 0.45 0.8 0.06 0.1 0.44 0.8 0.07 0.1 0.56 1.3 0.07 0.1 0.57 1.3 0.07 0.1 0.57 1.3 0.08 0.1 0.76 3.2 0.08 0.1 0.75 3.2

Blackmoor

Lane 0.1 0.1 0.27 0.4 0.1 0.1 0.27 0.4 0.12 0.1 0.34 0.5 0.12 0.1 0.34 0.5 0.12 0.1 0.34 0.5 0.12 0.1 0.52 1.0 0.12 0.1 0.52 1.1


61

TABLE 6.6: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High Tech

2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 0.61 1.5 0.3 0.4 1.23 46.1 0.32 0.5 1.33 64.2 0.33 0.5 1.29 56.6 0.33 0.5 1.52 89.1 0.39 0.6 2.9 159.9 0.38 0.6 3.13 190.3 0.39 0.6

Private

Access 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ascot Road

West 0.18 0.2 0.72 2.5 0.21 0.3 0.81 4.2 0.21 0.3 0.81 4.3 0.21 0.3 0.81 4.2 0.23 0.3 0.84 5 0.22 0.3 0.99 26.5 0.22 0.3 0.97 18.8

Ascot Road

north 0.59 1.5 0.17 0.2 0.68 2.1 0.18 0.2 0.68 2.1 0.18 0.2 0.68 2.2 0.18 0.2 0.69 2.3 0.18 0.2 0.81 4.3 0.18 0.2 0.81 4.3 0.18 0.2


62

TABLE 6.7: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD / WHIPPENDELL ROAD ROUNDABOUT


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Whippendell

Road 0.64 1.7 0.44 0.8 0.94 10.6 0.45 0.8 0.95 11.9 0.46 0.9 0.98 16.4 0.47 0.9 1.01 21.5 0.48 0.9 1.42 130.7 0.48 0.9 1.47 143.5 0.49 1

Ascot Road

Old 0.18 0.2 0.63 1.7 0.21 0.3 0.7 2.3 0.23 0.3 0.7 2.4 0.22 0.3 0.71 2.4 0.24 0.3 0.73 2.7 0.23 0.3 0.84 5 0.25 0.3 0.84 5.3

Ascot Road

north 0.48 0.9 0.2 0.3 0.56 1.3 0.21 0.3 0.57 1.3 0.21 0.3 0.58 1.4 0.22 0.3 0.58 1.4 0.24 0.3 0.66 2 0.24 0.3 0.67 2 0.24 0.3

Raven Close 0.13 0.1 0.01 0 999 9.5 0.01 0 999 9.5 0.01 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.9 0.02 0 999 10.2 0.02 0


63

TABLE 6.8: TRAFFIC IMPACT ANALYSIS: RICKMANSWORTH ROAD / ASCOT ROAD / WATFORD ROAD ROUNDABOUT


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Rickmansworth

Road 0.51 1.1 0.34 0.5 0.63 1.7 0.36 0.6 0.63 1.7 0.37 0.6 0.65 1.9 0.38 0.6 0.65 1.9 0.39 0.6 0.79 3.6 0.39 0.6 0.79 3.7 0.39 0.7

Ascot Road 0.24 0.3 0.65 1.9 0.26 0.4 0.7 2.4 0.27 0.4 0.71 2.4 0.27 0.4 0.71 2.5 0.28 0.4 0.73 2.7 0.27 0.4 0.81 4.2 0.28 0.4 0.81 4.3

Watford Road 0.73 2.7 0.41 0.7 0.78 3.5 0.44 0.8 0.78 3.6 0.44 0.8 0.79 3.7 0.45 0.8 0.79 3.8 0.46 0.9 0.82 4.6 0.49 1 0.83 4.8 0.49 1


64

TABLE 6.9: TRAFFIC IMPACT ANALYSIS: WATFORD ROAD / BALDWINS LANE ROUNDABOUT


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Access 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Watford

Road

West 0.78 3.4 0.65 1.9 0.88 6.6 0.7 2.4 0.88 6.8 0.71 2.4 0.89 7.2 0.72 2.5 0.89 7.5 0.73 2.7 0.94 11.5 0.73 2.6 0.94 12.1 0.74 2.8

Baldwins

Lane 0.51 1.1 0.18 0.2 0.59 1.4 0.19 0.2 0.59 1.4 0.19 0.2 0.6 1.5 0.19 0.2 0.6 1.5 0.19 0.2 0.62 1.6 0.19 0.2 0.62 1.6 0.19 0.2

Watford

Road

East 0.38 0.6 0.79 3.8 0.42 0.7 0.85 5.5 0.43 0.7 0.85 5.6 0.42 0.7 0.85 5.7 0.44 0.8 0.86 5.8 0.43 0.7 0.89 7.6 0.43 0.8 0.89 7.9


65

TABLE 6.10: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD OLD / MORRISONS ACCESS PRIORITY JUNCTION

Scenario 2021 + Committed

Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development

Time Period AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak AM Peak PM Peak

Arm RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q RFC Q

Ascot Road

Old Left

Turn 0.53 1.2 0.23 0.3 0.59 1.6 0.24 0.3 0.57 1.4 0.26 0.4 0.57 1.4 0.26 0.4 0.55 1.3 0.26 0.4 0.57 1.4 0.26 0.4

Ascot Road

Right Turn 0.23 0.3 0.09 0.1 0.33 0.5 0.12 0.2 0.35 0.6 0.23 0.3 0.35 0.6 0.23 0.3 0.26 0.4 0.2 0.3 0.35 0.6 0.23 0.3

Morrisons

Access

Right Turn 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0


66

6.44 The results of the analysis are now considered on a junction by junction basis.

Ascot Road New / Hatters Lane / Greenhill Crescent /Blackmoor Lane

Roundabout

6.45 Table 6.5 reveals that this junction continues to operate within capacity for all

scenarios, although the introduction of the High-Tech site results in the Ascot

Road arm marginally exceeding the 0.85 threshold during the AM peak, but not

to a degree where any associated mitigation is necessary.

Ascot Road New / Ascot Road Old (Morrisons Access) Roundabout

6.46 Table 6.6 reveals that this junction exceeds capacity for all scenarios other than

the 2016 existing, with the Ascot Road Old (Morrisons access) arm exceeding

capacity during the AM peak for all future year scenarios, primarily as a result of

the school during the future year baseline scenario when its fully operational.

6.47 Subsequent scenarios that includes additional development traffic generated by

the subject site then worsens that scenario. A mitigation strategy to address this

impact generated by the subject site is therefore necessary for this junction.

6.48 In terms of mitigation, as indicated on drawing number 16037-207, which

indicates the existing arrangement at this junction, the exit arm onto the Ascot

Road Old (Morrisons access) arm is sufficiently wide enough to accommodate a

dedicated right turn lane into the Morrisons service yard. Accommodating such

prevents the entry lane onto the roundabout from benefiting from a flared

approach.

6.49 It is therefore proposed to shift the existing pedestrian island north and shorten

the right turn lane into the Morrisons service yard, allowing for the introduction

of flared entry onto the roundabout. Keep clear markings are also added infront

of Ascot Road Old to allow traffic from the site to exit the junction should there

be occasions when the Ascot Road Old (Morrisons access) arm is in queue. A new

ARCADY model for the junction has therefore been created, with an entry width

of 6.5m and flare length of 12m. Table 6.12 below presents the results of this

modelling exercise for the future year scenarios.


67

TABLE 6.12: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT MITIGATION SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +


2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 0.73 2.6 0.24 0.3 0.79 3.6 0.25 0.3 0.77 3.1 0.26 0.3 0.87 5.8 0.3 0.4 1.21 44.5 0.29 0.4 1.31 62.3 0.3 0.4

Private

Access 0 0 0.3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ascot Road

West 0.21 0.3 0 4.2 0.21 0.3 0.81 4.3 0.22 0.3 0.81 4.2 0.24 0.3 0.84 5 0.23 0.3 0.99 26.5 0.23 0.3 0.97 18.8

Ascot Road

north 0.68 2.1 0.81 0.2 0.68 2.1 0.18 0.2 0.68 2.2 0.18 0.2 0.69 2.3 0.18 0.2 0.81 4.3 0.18 0.2 0.81 4.3 0.18 0.2

0


68

6.50 Comparing these results with the previous modelling runs indicated in Table 6.6,

it can be seen that the junction amendments address the impact generated by

the school and result in the junction operating within capacity with the additional

impact generated by the development, thus mitigating the development impact.

6.51 The junction amendment also results in the junction operating only marginally

over capacity during the AM peak with the cumulative impact generated by the

Ascot Road masterplan, but not to an extent where additional mitigation is

necessary.

6.52 The future year scenarios that include the High-Tech site however still witnesses

the Ascot Road Old (Morrisons access) arm road operating over capacity, although

significantly improved.

6.53 An additional mitigation strategy has therefore been prepared, which essentially

further reduces the right turn lane into the Morrisons service yard, allowing an

effective flare length of 26m to be introduced, indicated on drawing number

16037-208.

6.54 A new ARCADY model for the junction has been created for this additional

mitigation scenario, with the future year scenarios re-run.

6.55 Table 6.13 below presents the results of this modelling exercise for the future

year scenarios.


69

TABLE 6.13: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT ADDITIONAL MITIGATION

SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +


2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 0.63 1.7 0.22 0.3 0.69 2.2 0.23 0.3 0.66 1.9 0.24 0.3 0.75 2.9 0.28 0.4 1.00 14 0.27 0.4 1.08 25.7 0.28 0.4

Private

Access 0 0 0 0.0 0 0 0 0 0.00 0 0 0 0 0 0 0.0 0 0 0 0 0 0 0 0

Ascot Road

West 0.21 0.3 0.81 4.2 0.21 0.3 0.81 4.3 0.22 0.3 0.81 4.2 0.24 0.3 0.84 5.0 0.23 0.3 0.99 26.5 0.23 0.3 0.97 18.8

Ascot Road

north 0.68 2.1 0.18 0.2 0.68 2.1 0.18 0.2 0.68 2.2 0.18 0.2 0.69 2.3 0.18 0.2 0.81 4.3 0.18 0.2 0.81 4.3 0.18 0.2


70

6.56 Comparing these results with the previous modelling runs detailed on Table 6.6

and 6.12, it can be seen that the additional mitigation strategy to address the

cumulative impact of the High-Tech site results in significant improvements to the

junction beyond the future year baseline scenario without the Ascot Road

masterplan.

6.57 It is acknowledged however that this arm still operates over theoretical capacity

of 0.85 RFC, as does the Ascot Road west arm during the PM peak.

6.58 A more extensive mitigation strategy would therefore be necessary at this

junction, which would include the introduction of signal controls on the Ascot

Road New north arm and preceding circulatory part of the carriageway and the

Morrisons access arm, in order to create sufficient gaps to allow this traffic to

enter the junction. A desktop review has suggested that the traffic flows will allow

such an arrangement to occur within the existing roundabout form, due to the

low level of circulatory traffic accessing the Morrisons access road from the west.

Ascot Road New / Ascot Road Old / Whippendell Road Roundabout

6.59 Table 6.7 reveals that, whilst the junction operates within capacity during the PM

peak, during the AM peak this junction exceeds capacity for all scenarios other

than the 2016 existing, with Raven Close and Whippendell Road operating over

capacity, due to the volume of southbound traffic toward Ascot Road reducing

the availability of gaps for traffic to enter the junction from these arms.

6.60 Whilst the development does worsen this scenario, its relative impact is

negligible, resulting in only 5 additional vehicles in queue when compared with a

future year scenario where just the Ascot Road masterplan is in place.

6.61 A mitigation strategy is however necessary to address this impact. The exit arm

onto the Whippendell Road arm is generous enough for two lane exit, encouraged

by existing road markings, although the merge appears substandard, with existing

arrangement indicated on drawing 16037-209. The volume of traffic exiting onto

this arm does not however justify such a provision. It is proposed therefore to

amend the lane allocation at the roundabout and to shift the central island on

Whippendell north, allowing for the introduction of a third lane onto the junction

to accommodate a short flare, with the circulatory carriageway being of sufficient


71

width to accommodate these movements. This mitigation strategy is presented

as drawing 16037-210.

6.62 A new ARCADY model for the junction has been created, with the flare added, and

future year scenarios re-run. Table 6.14 below presents the results of this

modelling exercise.


72

TABLE 6.14: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD / WHIPPENDELL ROAD ROUNDABOUT MITIGATION SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Whippendell

Road 0.89 6.8 0.44 0.8 0.9 7.5 0.44 0.8 0.93 9.6 0.45 0.8 0.95 12.2 0.46 0.9 1.32 108.6 0.46 0.9 1.37 121.2 0.47 0.9

Ascot Road

Old 0.21 0.3 0.7 2.3 0.23 0.23 0.7 2.4 0.22 0.3 0.71 2.4 0.24 0.3 0.73 2.7 0.23 0.3 0.84 5 0.25 0.3 0.84 5.3

Ascot Road

north 0.56 1.3 0.21 0.3 0.57 0.57 0.21 0.3 0.58 1.4 0.22 0.3 0.58 1.4 0.24 0.3 0.66 2 0.24 0.3 0.67 2 0.24 0.3

Raven Close 999 9.5 0.01 0 999 9.5 0.01 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.9 0.02 0 999 10.2 0.02 0


73

6.63 Comparing these results with the previous modelling runs detailed on Table 6.7,

it can be seen that the improvements result in the impact of the development at

this junction being fully mitigated, achieving a nil detriment position, although it

is acknowledged the Whippendell Road arm still operates over capacity.

6.64 A similar position is reached relating to the cumulative impact including the Ascot

Road masterplan, with the improvements mitigating the additional impact

generated by the masterplan.

6.65 Whilst Raven Close operates over capacity during all scenarios, in reality there are

likely to be gaps occurring that will allow the small number of vehicle movements

generated by Raven Close to exit that site.

6.66 The introduction of the High-Tech site however results in a substantial worsening

of the situation, resulting in excessive queueing on Whippendell Road, requiring

a more substantial improvement strategy to mitigate this cumulative impact.

6.67 In terms of a wider mitigation strategy, HCC may take the view that they are

content with Whippendell Road to operate over capacity during a relatively short

period of the day, albeit significantly, given that improving its capacity would be

to the detriment of major traffic flows on Rickmansworth Road and Watford Road.

Similarly, it may be more beneficial for the operators at the High-Tech site to

implement a robust Travel Plan and/or reduce car parking provision in order to

reduce their respective traffic impact, although it is acknowledged that the

junction is operating over capacity prior to the introduction of the High Tech site,

meaning any additional traffic will have a significant effect.

6.68 Notwithstanding this, MA have undertaken some initial modelling exercises and

concluded that there may be an opportunity to address the issue by introducing

a significant change to the local highway network that would see the conversion

of the Ascot Road / Whippendell Road and the Ascot Road Watford Road

roundabout junctions into a signalised gyratory, allowing for east/west

movements between Watford Road / Rickmansworth Road to continue without

accessing the gyratory. The gyratory is necessary in order to provide sufficient

internal stacking space to accommodate the dominant southbound traffic from


74

Watford Road, whilst generating gaps to allow Whippendell Road traffic to enter

the junction.

6.69 This strategy would however require significant investment into the local highway

network in order to alleviate anticipated capacity constraints at a single, non-

strategic arm. HCC may consider therefore that such a proposal would be an

inefficient use of such investment.

6.70 Further detailed discussions with HCC on this junction are welcomed post

submission of the planning application.

Ascot Road / A412 Rickmansworth Road Roundabout


scenarios, with no mitigation necessary.

A412 Rickmansworth Road Roundabout / A412 Watford Road / Baldwins

Lane

6.72 Table 6.9 indicates that the junction begins to exceed capacity on Watford Road

(west) during the AM peak and Watford Road (east) during the PM peak during

the future year scenarios.

6.73 However, the subject site impact at the junction is negligible, resulting in less than

one additional vehicle in queue. It is not believed necessary therefore for a

mitigation strategy to be developed for this junction as result of the development

of the subject site or indeed the cumulative impact associated with the

development and the Ascot Road masterplan.

6.74 When the cumulative impact associated with the High-Tech site is added to the

network, again the impact on the capacity of the junction is not significant, with

queue lengths on Watford Road west increasing by 4 vehicles.

6.75 It is considered therefore that a mitigation strategy is not necessary at this

junction for this cumulative scenario.

6.76 However, should HCC deem a strategy is necessary, it is feasible for the effective

flare length on Watford Road west to be increased. Initial testing reveals that


75

increasing the flare length from 15m to 25m results in the Watford Road west arm

operating within capacity under all scenarios, including the additional impact

associated with the High-Tech site.

Ascot Road Old / Morrisons Access Priority Junction


scenarios.

6.78 Whilst it is acknowledged that the Ascot Road Old (Morrisons access) road will

suffer from queues, potentially blocking back over Ascot Road Old, the mitigation

strategy for that junction includes the introduction of keep clear markings that

will allow the vehicles to exit Ascot Road Old.

Closure of Ascot Road Old

6.79 Whilst not included as a specific proposal for consideration as part of the planning

application, the redevelopment of the site offers the potential to downgrade

Ascot Road Old and remove the through traffic from this location, therefore

improving pedestrian connectivity between the site and the station.

6.80 An additional modelling scenario has therefore been undertaken to assess the

impact of such a proposal. Initial results suggest that this would not have a severe

impact on the Ascot Road junction with the Morrison/Ascot Road Community

Free School access junction, with a slight worsening in queues on the Ascot Road

Old (Morrisons access) arm under the cumulative scenario with the introduction

of the High-Tech site, although previous assessments identified that this arm

would operate over capacity under this cumulative scenario, albeit improved with

a suggested mitigation strategy.

6.81 Further detailed assessments would however need to be undertaken to establish

the access strategies of other sites within the Ascot Road masterplan, as Ascot

Road Old would potentially need to be made two-way at the junction with

Whippendell Road to facilitate access to certain sites.

‘No Station’ Scenario

6.82 The introduction of Cassiobridge Station is a committed and funded development

that will be delivered. The scale and characteristics of the development proposal,


76

including in particular the proposed car parking ratios, are influenced by the

resultant improved accessibility.

6.83 However, should there be any concerns that Cassiobridge Station will not in fact

be delivered, an additional, ‘no-station,’ traffic modelling scenario has been

undertaken, applying more robust vehicular trip rates than those adopted within

the scenarios where the station is in place, to both the subject site and other

residential sites identified within the Ascot Road Masterplan.

6.84 The TRICS database has therefore been used to generate the revised trip rates. A

revised site selection criteria has been adopted, using residential sites consisting

of flats located within England, but outside of central London, but only including

edge of town and suburban sites, with edge of town centre and town centre sites

rejected. Again, sites that do not reflect a representative parking or bedroom ratio

have been rejected. This revised analysis resulted in a total of 15 private sites and

8 affordable sites, details of which are attached as Appendix P and Q, with revised

trip rates provided below Table 6.15.


77

TABLE 6.15: NO STATION SCENARIO TRIP RATES AND PREDICTED TRIP GENERATION

Vehicle All Person

AM Peak PM Peak Daily AM Peak PM Peak Daily

IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL IN OUT TOTAL

Private

Tenure

315 Units

Trip

Rate

Per

Unit 0.08 0.27 0.35 0.289 0.132 0.421 1.981 1.838 3.819 0.129 0.484 0.613 0.482 0.247 0.729 3.228 3.635 6.863

Trips 25 85 110 91 42 133 624 579 1203 41 152 193 152 78 230 1017 1145 2162

Affordable

Tenure

170 Units

Trip

Rate

Per

Unit 0.089 0.116 0.205 0.137 0.089 0.226 1.579 1.491 3.07 0.137 0.311 0.448 0.289 0.195 0.484 3.895 3.625 7.52

Trips 15 20 35 23 15 38 268 253 522 23 53 76 49 33 82 662 616 1278

Total 485 Trips 40 105 145 114 57 171 892 832 1725 64 205 269 201 111 312 1679 1761 3440


78

6.85 Comparing the trip generation between Table 6.15 and Table 5.1, it can be seen

that the revised site selection criteria under the ‘no station’ scenario generates

robust trip rates, with an increase in two-way traffic flows generated by the site

compared with the previous scenarios with the station in place, totalling an

additional 88 vehicular trips in the AM peak and 116 in the PM peak.

6.86 These revised trips have been distributed onto the local highway network using

the same distribution profile, indicated on Figures 6.39 and 6.40 for the AM and

PM peak respectively.

6.87 Capacity assessments of each of the off-site junctions have then been undertaken

for each of the future year scenarios, including:

2021 Future Year Baseline (Encompassing Committed Development,

which excludes the station) (Figures 6.41 and 6.42)

2021 Future Year Baseline Plus Development (Figures 6.43 and 6.44)

2021 Future Year Baseline Plus Ascot Road Masterplan (Figures 6.47

and 6.48, with total masterplan flows indicated on Figure 6.45 and

Figure 6.46)


Development (Figures 6.49 and 6.50)


Woodshots Meadow High Tech Site (Figures 6.51 and 6.52)


Woodshots Meadow High Tech Site Plus Development (Figures 6.53

and 6.54)

6.88 In terms of committed developments, the impact of the station, which was

sourced by comparing the Do Something ARCADY outputs with the Do Nothing

ARCADY outputs from the associated TA, has been removed. The station was

identified as generating a reduction in turning movements at some junctions as a

result of modal shift and an increase elsewhere and so its removal will have a

mixed impact on the local highway network.


79

6.89 In terms of the future year scenarios with the Ascot Road Masterplan in place, the

revised trip rates have been applied to the identified residential Masterplan sites.

6.90 Tables 6.16-6.21 below presents the results of the analysis for each junction,

allowing each scenario to be compared side by side. Again, the results of the

capacity assessment are presented in terms of RFC and Q, with full model outputs

provided as Appendix R.


80

TABLE 6.16: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / HATTERS LANE / GREENHILL CRESCENT /BLACKMOOR LANE ROUNDABOUT ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Ascot

Road 0.73 2.8 0.17 0.2 0.73 2.8 0.17 0.2 0.74 2.8 0.18 0.2 0.74 2.8 0.19 0.2 0.87 6.6 0.19 0.2 0.87 6.6 0.19 0.2

Greenhill

Crescent 0.26 0.4 0.41 0.7 0.26 0.4 0.41 0.7 0.31 0.5 0.44 0.8 0.31 0.5 0.42 0.7 0.42 0.7 0.43 0.7 0.42 0.7 0.43 0.7

Hatters

Lane 0.07 0.1 0.56 1.3 0.07 0.1 0.56 1.3 0.07 0.1 0.57 1.3 0.07 0.1 0.57 1.3 0.08 0.1 0.77 3.3 0.08 0.1 0.77 3.3

Blackmoor

Lane 0.12 0.1 0.34 0.5 0.12 0.1 0.34 0.5 0.12 0.1 0.35 0.5 0.12 0.1 0.34 0.5 0.13 0.1 0.53 1.1 0.13 0.1 0.53 1.1


81

TABLE 6.17: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +


2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 1.1 25.6 0.31 0.5 1.41 77.4 0.36 0.6 1.28 53.4 0.36 0.6 1.59 110.2 0.43 0.8 2.9 155.9 0.39 0.6 3.61 248.7 0.44 0.8

Private

Access 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ascot Road

West 0.21 0.3 0.81 4.1 0.21 0.3 0.72 2.5 0.22 0.3 0.84 5.2 0.23 0.3 0.86 5.8 0.23 0.3 1.0 30.4 0.22 0.3 1.02 40.6

Ascot Road

north 0.68 2.1 0.18 0.2 0.68 2.1 0.18 0.2 0.69 2.2 0.18 0.2 0.69 2.2 0.19 0.2 0.81 4.3 0.19 0.2 0.81 4.3 0.19 0.2


82

TABLE 6.18: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD / WHIPPENDELL ROAD ROUNDABOUT ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Whippendell

Road 0.96 12.9 0.47 0.9 0.97 14.3 0.5 1.0 1.03 27 0.49 1.0 1.07 37 0.55 1.2 1.47 144.5 0.51 1.1 1.53 159 0.55 1.2

Ascot Road

Old 0.21 0.3 0.71 2.4 0.24 0.3 0.73 2.7 0.24 0.3 0.74 2.9 0.27 0.4 0.76 3.2 0.24 0.3 0.86 6 0.28 0.4 0.88 6.9

Ascot Road

north 0.56 1.3 0.21 0.3 0.57 1.3 0.25 0.3 0.59 1.4 0.24 0.3 0.6 1.5 0.29 0.4 0.67 2 0.26 0.4 0.68 2.1 0.3 0.4

Raven Close 37.03 9.1 0.01 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.9 0.02 0 999 10.6 0.02 0


83

TABLE 6.19: TRAFFIC IMPACT ANALYSIS: RICKMANSWORTH ROAD / ASCOT ROAD / WATFORD ROAD ROUNDABOUT ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Rickmansworth

Road 0.64 1.7 0.36 0.6 0.65 1.9 0.39 0.6 0.67 2 0.38 0.6 0.68 2.1 0.43 0.8 0.8 4 0.4 0.7 0.82 4.3 0.43 0.8

Ascot Road 0.27 0.4 0.71 2.5 0.3 0.4 0.73 2.7 0.3 0.4 0.74 2.8 0.32 0.5 0.76 3.1 0.3 0.4 0.83 4.7 0.33 0.5 0.84 5.2

Watford Road 0.8 4 0.45 0.8 0.82 4.4 0.47 0.9 0.82 4.5 0.46 0.9 0.84 5 0.5 1 0.85 5.7 0.51 1.1 0.87 6.7 0.54 1.2


84

TABLE 6.20: TRAFFIC IMPACT ANALYSIS: WATFORD ROAD / BALDWINS LANE ROUNDABOUT ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Access 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Watford

Road

West 0.87 6.5 0.7 2.4 0.89 7.1 0.74 2.8 0.89 7.3 0.72 2.6 0.9 8.1 0.77 3.3 0.94 11.8 0.75 2.9 0.95 13.6 0.78 3.5

Baldwins

Lane 0.59 1.4 0.19 0.2 0.59 1.5 0.2 0.2 0.6 1.5 0.19 0.2 0.6 1.5 0.21 0.3 0.62 1.6 0.2 0.2 0.63 1.7 0.21 0.3

Watford

Road

East 0.44 0.7 0.85 5.5 0.44 0.8 0.86 5.9 0.43 0.8 0.86 6.1 0.45 0.8 0.87 6.4 0.44 0.8 0.89 7.9 0.45 0.8 0.9 8.6


85

TABLE 6.21: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD OLD / MORRISONS ACCESS PRIORITY JUNCTION ‘NO STATION’ SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Ascot Road

Old Left

Turn 0.52 1.2 0.23 0.3 0.59 1.6 0.24 0.3 0.56 1.4 0.25 0.4 0.64 1.9 0.31 0.5 0.56 1.4 0.29 0.4 0.64 1.9 0.31 0.5

Ascot Road

Right Turn 0.18 0.2 0.09 0.1 0.44 0.8 0.18 0.2 0.27 0.4 0.13 0.2 0.51 1.1 0.3 0.5 0.27 0.4 0.21 0.3 0.51 1.1 0.3 0.5

Morrisons

Access

Right Turn 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0


86

6.91 The results of the analysis are now considered on a junction by junction basis.

Ascot Road New / Hatters Lane / Greenhill Crescent /Blackmoor Lane

Roundabout

6.92 Comparing the results of Table 6.16 and Table 6.5 it is evident that there is no

change in the traffic impact at this junction under a ‘no station’ scenario, with the

introduction of the High-Tech site resulting in the Ascot Road arm marginally

exceeding the 0.85 threshold during the AM peak, but not to a degree where any

associated mitigation is necessary.

Ascot Road New / Ascot Road Old (Morrisons Access) Roundabout

6.93 Comparing the results of Table 6.17 with Table 6.6, it can be seen that under the

‘no station’ scenario, the junction performance improves during the

2021+Committed Development scenario as a result of the removal of the

additional traffic accessing the station, although the Ascot Road Old (Morrisons

access) continues to operate over capacity.

6.94 The additional traffic generated by the subject site worsens this situation and it

can be seen that each of the ‘with development’ scenarios under this ‘no station’

scenario result in a worsening performance.

6.95 The junction capacity has therefore been tested using the initial mitigation

strategy, with a 12m long flared entry and 6.5m wide entry width introduced on

the Ascot Road Old (Morrisons access) arm, with results presented below as Table

6.22.


87

TABLE 6.22: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT MITIGATION SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +


2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 0.66 1.9 0.24 0.3 0.84 4.6 0.27 0.4 0.75 2.9 0.28 0.4 0.94 9.8 0.33 0.5 1.2 41.6 0.3 0.4 1.49 95.6 0.33 0.5

Private

Access 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ascot Road

West 0.21 0.3 0.81 4.1 0.22 0.3 0.72 2.5 0.23 0.3 0.84 5.2 0.24 0.3 0.86 5.8 0.24 0.3 1.0 30.4 0.24 0.3 1.02 40.7

Ascot Road

north 0.68 2.1 0.18 0.2 0.68 2.1 0.18 0.2 0.69 2.2 0.18 0.2 0.69 2.2 0.19 0.2 0.81 4.3 0.19 0.2 0.81 4.3 0.19 0.2

0


88

6.96 Table 6.22 demonstrates that under this ‘no station’ scenario, the junction

amendments continue to address the impact generated by the school and the

subject site, thus mitigating the development impact.

6.97 Whilst the improvements are no longer sufficient to accommodate the cumulative

impact of the development and the masterplan, the junction performance is still

much better than the ‘2021 + committed development’ scenario without any

improvements in place, meaning a ‘nil detriment’ position has been established

for this cumulative scenario.

6.98 The future year scenarios that include the High-Tech site still however witness the

Ascot Road Old (Morrisons access) arm operating over capacity, although again

significantly improved.

6.99 The traffic flows have therefore been modelled using the additional mitigation

strategy at this junction, where the effective flare length of the Ascot Road Old

(Morrisons access) arm is increased to 26m, as indicated on drawing number

16037-208.

6.100 Table 6.23 below presents the results of this modelling exercise for the future

year scenarios.


89

TABLE 6.13: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD NEW / ASCOT ROAD OLD (MORRISONS ACCESS) ROUNDABOUT ADDITIONAL MITIGATION

SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +


2021 + Committed

Development +


+ Development



Ascot Road

Old

(Morrisons) 0.57 1.3 0.22 0.3 0.72 2.6 0.26 0.3 0.65 1.9 0.26 0.3 0.81 4.1 0.31 0.4 0.98 12.5 0.28 0.4 1.22 55.1 0.31 0.4

Private

Access 0 0 0 0.0 0 0 0 0 0.00 0 0 0 0 0 0 0.0 0 0 0 0 0 0 0 0

Ascot Road

West 0.21 0.3 0.81 4.1 0.22 0.3 0.84 5.2 0.23 0.3 0.84 5.2 0.24 0.3 0.86 5.8 0.24 0.3 1.0 30.4 0.25 0.3 1.02 40.7

Ascot Road

north 0.68 2.1 0.18 0.2 0.68 2.2 0.18 0.2 0.69 2.2 0.18 0.2 0.69 2.2 0.19 0.2 0.81 4.3 0.19 0.2 0.81 4.3 0.19 0.2


90

6.101 Comparing these results with the previous modelling runs, it can be seen that

under the ‘no station’ scenario, the additional mitigation provision fully addresses

the cumulative impact of the development and the masterplan in isolation and

the cumulative impact of the masterplan and the High-Tech site to a position of

nil detriment, recognising that the junction continues to operate over capacity

during this scenario. It is not however sufficient to mitigate the cumulative impact

of the masterplan, High-Tech site and the development proposal to a position of

nil detriment, a position that was established under the scenario where the

station is in place.

6.102 Again therefore, a more extensive mitigation strategy would be necessary to

address the cumulative impact associated with the High Tech site, involving the

partial signalisation of the roundabout to create sufficient gaps to allow this traffic

to enter the junction from Ascot Road Old (Morrisons access) arm.

Ascot Road New / Ascot Road Old / Whippendell Road Roundabout

6.103 Table 6.18 demonstrates that under the ‘no station’ scenario, Whippendell Road

continues to operate over capacity for all scenarios during the AM peak, with the

performance worsening during the future year scenarios that include the

cumulative impact of the masterplan and subject sites as a result of the higher

residential trip rates.

6.104 The capacity of the junction has therefore been retested using the previously

proposed mitigation strategy presented on drawing 16037-210, with results

detailed below in Table 6.24.


91

TABLE 6.24: TRAFFIC IMPACT ANALYSIS: ASCOT ROAD / WHIPPENDELL ROAD ROUNDABOUT MITIGATION SCENARIO


Development

2021 + Committed

Development +

Development

2021 + Committed

Development +

Masterplan

2021 + Committed

Development +

Masterplan +

Development

2021 + Committed

Development +

Masterplan + High

Tech

2021 + Committed

Development +

Masterplan + High

Tech + Development



Whippendell

Road 0.91 8 0.45 0.8 0.92 8.7 0.48 0.9 0.97 15.1 0.48 0.9 1.01 21.5 0.53 1.1 1.37 122.1 0.49 1 1.42 136.4 0.53 1.1

Ascot Road

Old 0.21 0.3 0.71 2.4 0.24 0.3 0.73 2.7 0.24 0.3 0.73 2.7 0.27 0.4 0.76 3.2 0.24 0.3 0.86 6 0.28 0.4 0.88 6.9

Ascot Road

north 0.56 1.3 0.21 0.3 0.57 1.3 0.25 0.3 0.59 1.4 0.25 0.3 0.6 1.5 0.29 0.4 0.67 2 0.26 0.4 0.68 2.1 0.3 0.4

Raven Close 37.04 9.1 0.01 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.5 0.02 0 999 9.9 0.02 0 999 10.6 0.02 0


92

6.105 Comparing these results with the previous modelling runs detailed in Table 6.7,

and reflecting the same position that was established against the scenarios with

the station in place, it can be seen that the improvements continue to be sufficient

to result in the impact of the development at this junction being fully mitigated,

achieving a nil detriment position. Again however, it is acknowledged the

Whippendell Road arm still operates significantly over capacity.

6.106 The improvements are, however, no longer sufficient to mitigate the cumulative

impact associated with the development and the masterplan under the ‘no

station’ scenario. The introduction of the additional impact associated with the

High-Tech site continues to result in a worsening of the situation, resulting in

excessive queueing on Whippendell Road, requiring a more substantial

improvement strategy to mitigate this cumulative impact.

6.107 MA have therefore revisited the wider mitigation strategy that involves the

conversion of the Ascot Road / Whippendell Road and the Ascot Road Watford

Road roundabout junctions into a signalised gyratory, with initial results

suggesting that the proposed gyratory would continue to operate within capacity

under the ‘no station’ scenario.

Ascot Road / A412 Rickmansworth Road Roundabout


scenarios, under the ‘no station’ scenario, with no mitigation necessary.

A412 Rickmansworth Road Roundabout / A412 Watford Road / Baldwins

Lane

6.109 Table 6.20 indicates that the junction continues to begin to exceed capacity on

Watford Road (west) during the AM peak during and Watford Road (east) during

the PM peak during the future year scenarios under this ‘no station’ scenario.

6.110 However, the subject site impact at the junction continues to be negligible,

resulting in less than two additional vehicles in queue. It is not believed necessary

therefore for a mitigation strategy to be developed for this junction as result of

the development of the subject site or indeed the cumulative impact associated

with the development and the masterplan.


93

6.111 When the cumulative impact associated with the High-Tech site is added to the

network, whilst the performance of the junction worsens than under the scenario

with the station in place, again the impact on the capacity of the junction is not

significant.

6.112 It is considered therefore that a mitigation strategy is not necessary at this

junction for this cumulative scenario.

6.113 Again however, should HCC deem a strategy is necessary, it is feasible for the

effective flare length on Watford Road west to be increased. Initial testing reveals

that increasing the flare length from 15m to 30m results in the Watford Road west

arm operating within capacity under all scenarios, including the High-Tech site,

under the ‘no station’ scenario.

Ascot Road Old / Morrisons Access Priority Junction


scenarios

No Station Summary

6.115 In summary therefore, under a ‘no station’ scenario, the previously proposed

mitigation would continue to be sufficient to fully mitigate the specific impact

associated with the development.

6.116 Reflecting the same position established as part of the analysis that was

undertaken for the scenarios with the station in place, a wider mitigation strategy

would however be necessary at the Ascot Road / Whippendell Road and Ascot

Road Old (Morrisons access) and Ascot Road New junctions in order to mitigate

the cumulative impact associated with the subject site, masterplan and High Tech

site.


94

Multimodal Impact Analysis

6.117 In terms of pedestrian impact, a revised PCGA has been undertaken for the

previous locations along Ascot Road and Croxley View.

6.118 For Ascot Road, it is assumed that all direct pedestrian and direct public transport

trips are reliant on this footway.

6.119 For Croxley View, it is assumed that all direct pedestrian trips are reliant on this

footway.

6.120 The results of the PCGA are included under Appendix H, with each location

achieving a rating of at least “A” during both peak periods, with the existing

footway provision therefore sufficient to accommodate the anticipated demand

generated by the proposed development, with sufficient capacity to

accommodate additional demand generated by committed development.

6.121 In terms of public transport input, the introduction of the Cassiobridge Station will

ensure that there is sufficient capacity to accommodate the demand generated

by commuters reliant on the London Underground and train network.

6.122 In terms of bus trips, there is likely to be capacity within existing provision to

accommodate the additional demand given the number of services that are

available from this location, particularly given the Croxley Rail Link will provide an

alternative route into Watford town centre.


95

7.0 SUMMARY AND CONCLUSIONS

7.1 Markides Associates have been instructed by Orion (Cassiobridge) Limited and

Leisure to prepare a Transport Assessment in support of their proposals for a

residentially led mixed use development proposal at a site located at Ascot Rd,

Watford, WD18 8AD.

7.2 The site is located within the authority boundary of Watford Borough Council and

is identified as an allocated site within their adopted planning policy

documentation.


buildings, currently occupied by a relocations and logistics firm with access taken

from Ascot Road Old. The development proposals are to demolish the existing

buildings, remove the existing points of access, and introduce a residentially led

development, with 4 blocks accommodating a total of 485 units, with a mix of unit

types and tenure. The development proposals also include a limited provision of

commercial floorspace, with intended occupiers to serve the demands of the site.

7.4 The site is an appropriate location for residential development, located adjacent

to a range of social infrastructure, encompassing residential, employment,

education and retail land uses, all of which are within an acceptable walk distance

of the site.

7.5 The accessibility of the site will also significantly improve in the near future, with

the introduction of Cassiobridge Station immediately opposite, which will form

part of the London Underground network, accommodating Metropolitan Line

services between Watford town centre and central London. The station will be

supported by an associated commuter car park.

7.6 Residents of the site will not therefore be reliant on travel by car to access

essential services, which has influenced the proposed car parking strategy for the

site, with parking provision of approximately 0.38 spaces per unit, accommodated

within an undercroft parking area accessed from Ascot Road Old. This level of

parking is justified based on the site’s accessibility, with planning policy inferring

that a reduction below adopted and emerging parking standards is acceptable for


96

sites located such as this. Whilst it is acknowledged that some areas surrounding

the site are not located within an established Controlled Parking Zone, the

Applicant is willing to contribute toward its introduction if deemed necessary.

Indeed it is likely that some provision may be necessary to mitigate the potential

of commuters to the new station parking within local residential streets to avoid

paying within the associated car park.

7.7 Further measures will be implemented to reduce latent parking demand,

including the implementation of a robust Travel Plan and Car Club, with the

Applicant funding a marketing package that promotes the Car Club to residents.

7.8 The development proposals include a delivery and servicing strategy that requires

the introduction of dedicated loading bays along the Ascot Road Old site frontage,

with emergency and occasional service vehicle access accommodated on-site via

the inclusion of shared surfaces across the layout.

7.9 The Transport Assessment has used a TRICS based assessment to quantify the

anticipated vehicular trip generation associated with the scale of development as

57 vehicle movements in the AM peak and 56 in the PM peak.

7.10 The Transport Assessment has then undertaken a traffic impact analysis of a

number of off-site junctions within the immediate area and identified that the

impact of the development can be readily accommodated. There are, however, a

couple of junctions where some localised amendments are necessary to fully

mitigate the impact of the subject site.

7.11 These amendments include introducing flared entry on the Ascot Road Old arm

that provides access to Morrisons at the roundabout junction with Ascot Road

New, by reducing the width of the exit lane at this arm of the junction.

7.12 A similar strategy is proposed for the Whippendell arm of the roundabout junction

with Ascot Road, with the introduction of a third entry lane at the junction.

7.13 The Transport Assessment has also undertaken a cumulative impact assessment,

where it has been demonstrated that, based on the same car parking and trip

generation assumptions, with the mitigation referenced above, the additional


97

impact generated by the Ascot Road masterplan can also be accommodated

without generating a severe impact, although it is acknowledged Whippendell

Road continues to operate over theoretical capacity during this cumulative

scenario.

7.14 The Transport Assessment has also undertaken a cumulative impact assessment

that includes the additional impact associated with an emerging development

proposal at the Woodshots Meadow High Tech Site, which promotes the

introduction of a large scale of B1 Office development and associated car parking.

The analysis has demonstrated that this additional development has a significant

impact on the capacity of the local highway network, requiring additional

mitigation strategies.

7.15 The Transport Assessment has identified that the proposed flare entry on the

Ascot Road Old Morrisons access arm could be extended to deliver additional

capacity to the junction and whilst the arm will continue to operate over capacity

the flare extension results in an improvement. A more extensive improvement

strategy may be necessary at the junction to fully mitigate the impact of the High-

Tech site, which would include signalising approaches.

7.16 The Transport Assessment has also identified that marginal capacity constraints

at the Watford Road arm of the junction with Baldwins Lane could be addressed

through the extension of the existing flare, bringing this arm into capacity under

all scenarios.

7.17 With regards to the Whippendell Road junction with Ascot Road, the introduction

of the High-Tech site worsens the performance of Whippendell Road, resulting in

extensive queues. Markides Associates have undertaken an exercise that

demonstrates that the potential change of this junction and the adjacent Watford

Road / Ascot Road junction to a gyratory, could allow the introduction of sufficient

storage space for southbound vehicles to be held at a signal junction, allowing

Whippendell Road traffic to enter the gyratory. However, this would prove a

costly measure. A more appropriate measure would be for the High-Tech site to

promote sustainable travel amongst the workforce and adopt a parking strategy

that reduces the impact as much as possible. It is envisaged that more detailed


98

consideration of the options for this junction are considered as part of the

application.

7.18 Should mitigation strategies be necessary, these should be proportional to the

impact of the development compared with the impact of the wider masterplan

and other emerging developments.

7.19 The Transport Assessment has also reviewed relevant policy at national, regional

and local levels and found the proposals to be compliant.

7.20 On this basis, Markides Associates are of the view that that there is no transport

related reason why the proposals should not be supported, with NPPF stating that

development should only be prevented or refused on transport grounds where

the residual cumulative impacts of the development are severe.

Ascot Road, Watford€¦ · 16037-01-R02B Ascot Road, Watford – Transport Assessment i CONTENTS...

Documents

Transcript of Ascot Road, Watford€¦ · 16037-01-R02B Ascot Road, Watford – Transport Assessment i CONTENTS...