On the impact of fast route geometry in London with some strategic applications

Les Mayhew Cass Business School

International Geographical Union (IGU) conference Leeds University, 2013

lesmayhew@googlemail.com

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Geographical theory and urban analogues

Classical geographical theory•Central place theory, hierarchies, economic efficiency, spatial equilibrium, accessibility•Optimum location of the firm, market areas, competition•Minimisation of production, distribution, and environmental costs•Travelling salesman involving delivery systems, problems involving minimisation of travel costs•Network assignment problems, queuing theory, modal split, shortest paths

Urban analogues• Retail centres, health care facility location,

administrative centres • Airport and railway hubs, out of town retail

centres, river crossings• Assembly systems, warehousing, delivery

systems (e.g. parcels, food)• Emergency response systems (police, fire,

ambulance)• Road charging, traffic management, air

quality • Strategic planning and public policy

(housing, employment and public transport)

• Green Belt and parks

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Challenges and tools• Spatial representation and mapping of urban areas –

concentric, multi-centred, coastal, estuarine• Urban metrics – not undifferentiated planes but a more

complex geometry (e.g. networks, non-Euclidean, or other geometry)

• How to integrate spatial decision making with economic aspects viz. generalised costs of travel, cost-benefit analysis

• Spatial and mathematical tools which should be simple to understand, general and abstract from reality i.e. based universal principles and transparent assumptions

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Structure Urban spatial metrics and key spatial concepts

– a refresher Introduction to properties of orbital radial

metrics Overview of applications including congestion

charging, airport location, river crossings and urban structure

Concluding remarks

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Travel within urban areas: Alternative metrics

Euclidean travel in undifferentiated plane

Time-Cost minimisation (non-Euclidean)

Cartesian (‘Manhattan’ metric)

Double radial metric

Orbital – radial metric

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Basic geometric conceptsAreas and isochrones

X

Isochrones and shortest paths

Route catchments

Market areas

Regular tessellated market areas

t

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Fundamental time surfacesTime surfaces are 3-D representations on which distance equates to travel time. Distance is measured in minutes or hours and areas in square minutes or hours. Patterns on time surfaces such as tessellated market areas can be transformed to the urban plane and their properties studied. Fundamental surfaces include the cylinder, cone, sphere and plane

Source: Hyman and Mayhew 1984

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Tessellated urban planes based on different underlying time surfaces

These tessellations are generated from 3-D time surfaces and show the intricacies of tessellated patterns achievable. In these cases average travel speeds increase with distance from the city centre. Every market area however has the same travel time radius, the sizes of which are a function of local travel speeds and road configuration.

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Example: 10-minute isochrones around A&E centres

Local movement constricted by local road configuration and traffic density. Movement in outer areas less constricted and so fewer centres are needed This map is based on average speeds increasing according to

Map based on access to local A&E centres in London. Around each centre is drawn a 10-minute isochrone. The isochrones do not tessellate as in the time surfaces but in the real world we can always expect imperfection. With GPS systems and data extractable from systems such as Google Map the data exist to calibrate such maps with considerable accuracy.

33.0rV 9

Route catchments and isochronesConcentric city with radial and orbital movement

C

D

quickest paths isochrones route catchment

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Urban orbital-radial metric in concentric cities

AVrrt /)( 21

BAA VRVrRVrRt //)(/)( 21

Travel time via centre

Travel time via ring

R = ring radius VA= radial speed

R1= fixed trip end VB=orbital speed

R2= variable trip end k=VA/VB

=angle between R1 and R211

Test of orbital efficiency Catchment Maps (for r1>R)

Fails test of ‘extreme merit’Example: London N-SCircular Road

Orbital

Radial Radial

Orbital

Orbital

Passes test of ‘extreme merit’Example: London M25Motorway

Case: VR / VO >2/ Case: VR / VO < 2/

Orbital

Orbital and radial route catchments based on an exterior destination north of the city centre destination located outside the orbital

destination destination

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Congestion charging

• Introduced in London in 2003

• It covers an area of about 3km in radius

• It aims to reduce congestion and raise funds for London's transport system

• It costs £10 a day between 7:00 and 18:00 on weekdays

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Spatial impact of central congestion charging on route catchments in a 3-ringed city

Route catchment maps for two fixed locations: (A) At 7.5 kms, no charge; (B) At 18.5 kms, no charge; (C) At 7.5 kms, charge applied; (D) At 18.5 kms, charge applied

Maps demonstrating the power of congestion charging to re-direct traffic and the need to measure effects over a wide area. Route catchments are based on four routing options consisting of three orbital routes and radial travel

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Strategic river crossings – building a new bridge in east London

j

i

rj

ri

R1

R2

k=1k=2k=3k=4k=5

j

i

rj

ri

R1

R2

k=1k=2k=3k=4k=5

Possible routes

1. Double radial (via city centre) 2. Inner ring clockwise3. Inner ring anti clockwise4. Outer ring clockwise5. Outer ring anti -clockwise

Key to notation‘k’ are river crossing pointsCharges are applied at k1 and k2; k4 and k5 are toll freeA congestion charge is applied to journeys passing through the central charging zone (k3)Costs based on monetised travel time plus toll or congestion charge

River Thames

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Images of strategic crossing points in east London

£2.00

Inner ring – Woolwich ferry Outer ring – Dartford crossing

Inner ring bridge design New cable car crossing Central London congestion charge £10

free

? £3.20

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Total market capture of old and new river crossing

-20

-10

0

10

20

y

-20 -10 0 10 20

x

Inner ring

Outer ring

15%

20%

25%

15%

20%

25%

-20

-10

0

10

20

y

-20 -10 0 10 20

x

Inner ring

Outer ring

-20

-10

0

10

20

y

-20 -10 0 10 20

x

Inner ring

Outer ring

Inner ring

Outer ring

15%

20%

25%

15%

20%

25%

key

Impact zone for new bridge

Impact zone for old bridge

New and old bridges 17

Outer ring radius 25kms

Inner ring radius 12.5 kms

Different locations have different route market shares. Contour values at any given location represent the percentage of traffic using a particular route. The higher the market share the busier the route is expected to be at that location and the greater its influence over traffic at any point

Should London build a new airport in the Thames Estuary?

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Artist’s impression of new airport and its proposed location in the Thames estuary about 66 kms from the city centre

Two attraction problem in an orbital-radial urban area: Example of two airports

Two airports A,B with slow orbital road

Two airports A,B with fast orbital road

Radial market area, A Orbital market area B

Orbital market area A

Ring road

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The concept of eclipsed market areas and their importance in locating new airports

Internal

Map showing inner and outer eclipse envelopes for a 3-attraction example. Shaded areas are eclipsed

External and Internal Eclipsed Regions for attraction A

External

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The market area of any proposed new airport which is located in the shaded region of either map would be eclipsed by existing airports

Introduction of new airport in east London but will it be ‘eclipsed’ before it is built?

Radial market

area

Locations and market areas for four and five regional airports. The circle represents the M25 orbital route. Inner and outer eclipse envelopes are also shown (A = Heathrow; B = Luton; C = Stansted; D= Gatwick)

A location on the east side of London makes strategic sense and would be a good strategic fit with the other regional airports

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But is the proposed location viable?

0%

10%

20%

30%

40%

50%

60%

33 39 45 51 57 63 69

Radius of new facility (kms)

Ma

rke

t sh

are

Heathrow

Luton

Stansted

New

Gatwick

Chart shows how the market share of existing airports adjust according to the distance of the location of the new airport from the city centre.

The new airport would capture nearly 30% of the geographical market if it located at or near the M25 but this would reduce zero if it were twice this distance from the centre (proposed location is 66kms from the city centre)

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Market areas in orbital radial networks

Inside boundary

Outside boundary

Trips divert through centre

Orbitals

(a) (b)

Service area enclosed by isochrone situated on a fast orbital – two cases. The area enclosed by the isochrone

in case (a) is given by:22 tVVA BA

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Tessellating concentric urban areas with multiple ring roads

A B

C D

E

Tessellated concentric hypothetical urban areas with one to five rings and six facilities per ring:

• 12.5kms gap between rings

• Radial velocity 50 kph

• Maximum travel time radius to nearest centre is 15 minutes

• Orbital travel time 3 hours

• Ring speeds proportional to distance from city centre

• Inner ring service area 164 sq km; out ring 818 sq km

• Six facilities per ring

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‘All-purpose speed’ in interstitial areas

(a) 50kph (b) 25kph (c) 10kph

Areas spanned in given travel time radius

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Where there are a finite number of fast radial routes it may be useful to distinguish between speeds achievable on the fast routes from the interstitial ‘all-purpose’ routes

Abercombie Greater London Plan (1944)

E

DC

AB

(A) (B) (C)

(A) Abercrombie’s arterial system; (B) ‘Tessellated version of Abercrombie; (C) tessellated version with slower interstitial road speeds. There are ten fast radials with 5 orbital-radial intersections on each ring

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Arterial (motorway standard)

Sub-arterial major roads

Basic standard

Does Abercrombie’s ring structure work?

• Ring B the ‘inner ring’ is of ‘merit’ as is ring D, both of which are designated motorway standard

• The outer-most ring E could be of merit but it was not designated motorway standard in the plan

• Ring C, the current N&S circular is not of merit but should be

• Ring A corresponds almost exactly to the current central area congestion charging zone and has assumed much greater importance

• The analysis also suggests the need for a ring ‘O’ which would be of approximately 1-2kms radius inside the current congestion charging zone and pedestrianised. This has been included in the previous slide

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Comparison with today• The London orbital M25 combines features of

Abercrombie’s two outer rings D and E• Ring A corresponds with the London congestion charging

Zone• Ring B the inner motorway ring was abandoned in the

1970s• Ring C the N&S Circular has been improved in parts but

does not join up• Ring E exists but is not fully joined up and is not considered

‘strategic’• A few radials of motorway standard have been

constructed but most terminate at or around the M25 orbital instead of ring B as envisaged

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What’s changed and why was plan not completed?

• Conflict between high street retailing and accommodation of through traffic in high streets• Conflicted with the preservation of character and built form of local areas• Switch in philosophy from car accommodation to car containment

- Congestion charging- Speed limits- Parking restrictions- One-way systems- Local improvements- Public transport improvements- Low emission zoning- Pedestrianisation- Cycle ways- Planning restrictions and land use

• Competition from out of town centres e.g. located on or near orbitals • More recently competition from internet retailing and increasing home delivery of goods and

services

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Conclusions• Urban spatial theory has stalled, not much progress as far as

one can tell• However, visionary proposals are becoming more

commonplace and are in fashion again• Theories are needed to validate these visionary ideas and to

inform new proposals and data collections• Working with different geometries has much to offer and

further to go• Important that theory does not run too far ahead of practice

and vice-versa• Use of geometry as a precursor and to explore options can

save money and speed up planning and evaluation

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References• Hyman, G. and L. Mayhew.(2008) Toll optimisation on river crossings serving large cities. Transportation Research A. 42(1) 28-47

• Hyman, G. and L. Mayhew.(2004) Advances In Travel Geometry and Urban Modelling. GeoJournal 59, 191-207. • Hyman, G. and L. Mayhew.(2001) Market area analysis under orbital-radial routing with applications to the study of airport location.

Computers, Environment and Urban Systems, Vol 25,195-222 • Hyman, G. and L. Mayhew (2001) Reassessing Urban Space Using Fast Route Geometry. In Transport Planning, Logistics and Spatial

Mismatch, 5-21. Pion, London. • Hyman, G. and L. Mayhew (2002) Optimising The Benefits Of Urban Road User Pricing. Transport Policy Vol 9, 189-207. • Mayhew, L. (2000) Using Geometry To Evaluate Strategic Road Proposals In Orbital-Radial Cities. Urban Studies Vol 37, 13, 2515-2532. • Hyman, G,.and L. Mayhew (2000) The Properties of Route Catchments in Urban Areas. Environment and Planning B., Vol 27, 843-863. • Hyman, G. and L. Mayhew (2000) Fast Route Geometry in Urban Areas. Environment and Planning B., Vol 27, 265-282. • Mayhew, L. (1986) Urban Hospital Location. London Research Series in Geography.. George Allen and Unwin, London • Hyman, G. and Mayhew, L. (1983) On The Geometry Of Emergency Service Medical Provision In Cities. Environment and Planning A, Vol

15, 1669-1690.

• Mayhew, L. (1986) Urban Hospital Location, George Allen and Unwin, London. • Mayhew, L. (1981) Automated Isochrones and the Location of Emergency Medical Services in Cities. Professional Geographer 33(4),

423-428.

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