1. Introductiononlinepubs.trb.org/onlinepubs/webinars/150611.pdf · o HCM and Rodel both utilize...

Outline

1. Introduction

2. Basis of Rodel 10 mins

3. Transferability and Validation 10 mins

4. Program Inputs and Outputs 10 mins

5. Demo of Program 10mins

Rodel - OutlineRodel - Outline

• Analysis process that facilitates convergence of design solutions to meet operational objectives

• Quickly explore / identify viable alternatives for given flows, site constraints and project objectives

• Particularly well suited for:o Constrained, high-flow locationso Flared entries, corridors

Huffman Road Corridor, Anchorage, AK

Rodel - IntroductionRodel - Introduction

o Originally released in 1986 in the UK

o Used by many agencies and consultancies across US since ~1992

• Major Update in 2012: RODEL V1-Windows (current v1.88)o Conformance with North American Design and Analysis Practices

Right (or Left) Hand Drive

English (or Metric) Units

U.S. Peak Hour Factor (PHF)

Original Synthesized input

Original Direct Input features

o Print Selection Menu for Documentation

o Importantly it has maintained its unique interactive interface


Rodel users around the world

• Capacity Models (Calibration for each)

o Empirical Model - Kimber/Hollis,TRL LR942, 1980o Rodel v1.88 extends the application of Kimber’s equations to US/North American design practices

and principles

o By-Lane Inputs Determine “Effective Geometry”

o Full integration of the 2010 HCM Capacity Model Identical results to HCS

(HCM2015 update forthcoming)

• RT Bypass Lane Modeling (Full and Partial/Yield)

• Crash Prediction Models & Economic Analysis

o US and UK Intersection and Approach Level crash prediction methodologies to derive injury and damage-only crash ratios from geometric parameters, safety criteria, and traffic flows

o Crash and Delay costs are derived from user input values for each


Rodel’s user interface developed to facilitate understanding of analysis and explore the design envelope for solutions

• Input and outputs are:o Explicit numerical values (no unknown factors)

o Informs analyst/designer of the geometric and operational interrelationships

o Interactive and educational user interface –pop-up help and embedded user manual


Rodel’s user interface includes:

• Sensitivity Testing - “What if” scenarios o Increase/decrease % of traffic for specific

approaches - tests robustness of the designo Test with reduced capacity (due to context –

on-street parking, environmental/snow)o Assess the potential for unacceptable queues or delayso View output simultaneously to easily explore geometry to

achieve acceptable queues and delays


Traffic Planning:• User-specified

operational parameters of Delay, 95% Queue, V/C Ratio

• Output: Sets of geometric parameters to meet targeted parameter


Full Geometrics:• Refines Geometry

• Bypass Lane Modeling

• Pedestrian Capacity Effects

HCM Compliant

o HCM and Rodel both utilize ‘Time Dependent Queuing Theory’ (developed by US researcher P.M. Morse)

o Delay is derived from queuing theory equations; therefore,nothing in this respect is different from HCM to Rodel

o However, Rodel incorporates ‘High Definition’ Queuing theory equations (via time slices) that adjust for varying v/c ratios

o This provides stability over the entire range of v/c ratios,exceeding 1.0 Provides accurate operational predictions at higher v/c ratio conditions

– HCM simplified single equation - stable to ~0.90

Rodel’s - IntroductionRodel’s - Introduction

Basis of Rodel – Empirical Model

UK Research Development

• 1960-70s congestion relief -national imperative in the UK

• Significant design experimentation was conducted on congested/fully saturated roundabouts

• Existing analysis methods were not matching observed operations

• Desired an accurate analysis methodology anchored to the design geometrics directly

• Statistical – Regression analysis approach was undertaken

Research Basis Background

Modifications to large congested roundabouts

Basis of Rodel - Empirical ModelBasis of Rodel - Empirical Model

TRL Kimber / Hollis (LR 942)

• 1980 UK published Kimber / Hollis Capacity Equations (LR 942) – 11,000 min of “at-capacity”

analysis of 86 roundabout entries over the full range of geometries and traffic volumes.

• Re-checked the equations and found them to be very stable, no changes required– Stability is attributed to the

large statistical database collected over the full range of geometric and traffic flows


GEOMETRY

CAPACITY

LaneInteraction

Kimber’s Equations

gap forcing

priorityreversal

Merging

Driver behaviorvariation described directly via the geometrics

Significant departure from their existing gap-based procedures

Basis of Rodel - Empirical Model Basis of Rodel - Empirical Model

E V

L

2Ø

D

6 Parameters

Started with 35 geometric parameters, then 16, to 9, and finally 6 statistically significant

Kimber / Hollis (LR 942)

Basis of Rodel - Empirical Model Basis of Rodel - Empirical Model

6 Geometric Inputs3 Major Capacity Variables

• Entry Width (E)

• Approach Width (V)

• Effective Flare Length (L’)

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

1 6 0 0

4 5 6 7 8 9 1 0 11 1 2 1 3 1 4E n tr y W id th E (m e tre s )

Capa

city

(Pc

us)

Capa

city

(Pc

us)

1 0 0 0

1 2 0 0

1 4 0 0

1 6 0 0

1 8 0 0

0 1 2 3 4 5 6 7 8 9 1 0H a lf W id th V (m e tre s )

Cap

acity

(Pc

us)

Cap

acity

(Pc

us)

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0

F la re L e n g th L ' (m e tr e s )

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

1 6 0 0

6 0 0

8 0 0

1 0 0 0

1 2 0 0

1 4 0 0

0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 08 0 0

1 0 0 0

1 2 0 0

1 4 0 0

1 6 0 0

E n try R a d iu s R (m e tr e s )

0 2 0 4 0 6 0 8 0 1 0 0E n try A n g le N ( d e g )

3 0 4 0 5 0 6 0 7 0 8 0

In s c r ib e d C irc le D ia m e te r D ( m e tre s )

Basis of Rodel - Empirical ModelBasis of Rodel - Empirical Model Research has Established the Geometric Relationships

V E

L’ D

R PhiD = 180ft

D = 300ft

Circulating Flows

Cap

acity

(D)

3 Minor Capacity Variables

• Entry Radius (R)

• Entry Angle (Φ)

• Diameter (D)

Basis of Rodel - Empirical ModelBasis of Rodel - Empirical Model3 Major Capacity Variables

Approach Width

Entry Width

Flare Length (L’)

Basis of Rodel - Empirical ModelBasis of Rodel - Empirical ModelMinor Capacity Variables

Rad

Phi

Radius

Entry Angle

“Phi” is half the measured angle

R

R

Understanding Capacity Mechanisms • Allows for convergence of desired Operational Objectives

within available space and context

AVOID UNDERDESIGN (less capacity than required): – Early Congestion

• High levels of delay• Poor public opinion

AVOID OVERDESIGN (more capacity than necessary):– More entry lanes required

• Larger, faster, less safe geometry • Greater impacts, more right-of-way • Higher costs• Less feasible

Basis of Rodel - Empirical Model

U.S. Validationand Transferability for

North American Practices

Are UK drivers more accustomed to roundabouts, producing higher capacities?• Possibly smaller cars or smaller

trucks?

Single-Lane Entry Widened For Trucks, Not CapacityUS vs UK Design Practices

Researchers confused a widened single-lane entry for trucks with a flared entry design

Rodel’s Transferability and ValidationRodel’s Transferability and Validation

Enhanced Empirical Model (lane-based) • By-lane inputs determine “Effective Geometry”

• Avoids incorrect use – overestimation of capacity


nc+

nc

Leg1

ne

Leg 2

Kimber LR 942 – Single-Lane Capacity

1,130

Kimber LR 942 matches US Data

Rodel’s Transferability and ValidationRodel’s Transferability and ValidationSingle-Lane Entry Widened For Trucks, Not CapacityUS vs UK Design Practices

Kimber LR 942 – Flared 2-Lane Capacity

1,800


Rodel matches US Data

Larger Curvilinear Single-LaneUrban Single-Lane

Rodel Prediction vs US Data Rodel Prediction vs US Data

FHWA TOPR34 Data: will be used to develop a new HCM2015 model

Rodel’s Transferability – Single Lane Prediction vs US DataRodel’s Transferability – Single Lane Prediction vs US Data

2,126

1,100

Rodel’s Transferability – Dual Lane Prediction vs US Data Rodel’s Transferability – Dual Lane Prediction vs US Data

1,180

FHWA TOPR34 Data: will be used to develop a new HCM2015 model

Rodel Slope and Intercept output easily accessible on main screen

2,126

Rodel Cap Line

HCM 2010

2012 Data

Analysis forAll Types of Roundabouts

Accurate Operational Assessment for All Types of Roundabouts

Pho

to: W

erne

r B

rilo

n

Small Urban Compact Larger Curvilinear Single-Lane

• 80’ ICD• Narrow entry width E= 12’• Small entry radii R = 25’ • Perpendicular entries Phi ~ 60 deg.

• 145’ ICD• Wider entry width E = 14’ • Larger entry radii R = 60’ • Curvilinear entry Phi ~ 20 deg.


Large Multi-Lane

• 125’ ICD• Flared Two-Lane Entry• Single-Lane Entry • Aux RT Lanes (two types)

• 225’ ICD• Flared Off-Ramp Entry• Two and Three-Lane • Aux RT Lanes (two types)

Compact Flared Multi-Lane Entries

Accurate, Versatile, Robust Operational Assessment for All Types of Roundabouts

Rodel’s StrengthsRodel’s Strengths

Hybrids, Turbos, Urban Compact, Rural High-Speed

Rodel’s Strengths – Single LaneRodel’s Strengths – Single Lane

Single Lane Exit

Single Lane Approach

Single Lane Circulating

Rodel’s Strengths – Single LaneRodel’s Strengths – Single Lane

Single Lane Entry

Yield RT Bypass Lane

Single Lane Entry

Full RT Bypass Lane


Rodel’s Strengths – Bypass ModelingRodel’s Strengths – Bypass Modeling

Rodel’s Strengths – Hybrid and Turbo/Spiral Designs Rodel’s Strengths – Hybrid and Turbo/Spiral Designs - Single Lane / Multi-Lane- Flared or Parallel Entries- Hybrid / Turbo /Spiral- Bypass Lanes

Two Lane Entry


Two Lane Entry

Merge RT Bypass Lane

Single Lane Entry

Two Lanes Circulating

Flared Entry


Single Lane Circulating

Two Lane Exit

Flared Entry

Merge Bypass Lane

Three Lane Entry

Full RT Bypass Lane


Three Lane Exit

Three Circulating Lanes

Rodel’s Strengths – Multi-Lane 3-4 lanes, Bypass LanesRodel’s Strengths – Multi-Lane 3-4 lanes, Bypass Lanes

Merge or Full Receiving downstream lane Bypass Lane

Merge downstream Bypass Lane

- Single Lane / Multi-Lane- Flared or Parallel Entries- Hybrid / Turbo /Spiral- Bypass Lanes

Exit Roadway Width (Ex)Number of Lanes (n)

Circulatory Roadway Width (c)Number of Lanes (n)

Entry Width (E)Number of Lanes (n)

E

Approach Width (V)Number of Lanes (n)V

Flare Length (L)E+V

2

L

E=22’

11’’

V=12’

12’

L=150’

11’’

17’

Rodel’s Strengths – Flared EntriesRodel’s Strengths – Flared Entries

Program Overview

Main Screen - Empirical Capacity Model

Geometry

Traffic

Results

Rodel’s InterfaceRodel’s Interface

Main Screen - HCM Capacity Model

Geometry

Traffic

Results


Project Information (Open or New, Print Menu, +/- Legs, Notes, Exit flows, Time Slices)


Project Information (Model, Delay (Control or Queue), Input ( PHF, Direct, Synthetic) Peak am/pm)


Lanes/Geometric Inputs, Capacity Modifiers


Geometry

Visual Geometry Editor


Geometry

Secondary Input (Calibration, Crash, Economic, Bypass)


Secondary Inputs

• Transition• Secondary

– Bypass– Calibration– Safety/Economic analysis

Rodel Interface – Secondary Inputs

Calibration, Accidents, Economics, Bypass Lanes


Calibration – Empirical Model

Embedded Help TutorialEmpirical Calibration

Rodel InterfaceRodel Interface

Calibration - HCM Model

HCM2010 Calibration HCM2010 Calibration - tf

HCM2010 Calibration - tc


Choose Accident Model


Output in Rates/M entering or number of crashes by type


AADT from PH

Accident Models Economic Evaluation



Embedded Tutorial – Bypass Lanes

‘Full’ Bypass Lanes

Downstream MergeCondition

Free


Embedded Tutorial – Bypass Lanes

‘Yield’ Bypass Lanes

1 or 2 Lanes typ.


Results (Flow rates, v/c, Delay, Q, 95Q, LOS)

Results


Results Output – Slope and Intercepts

ResultsCapacity


Results Output - Accidents

ResultsAccidents


Results Output - Accident Rates

ResultsAccident Rates


Results Output - Economics

ResultsCosts


Results Output - Global

ResultsGlobal


Embedded Help Pop-ups

Main Screen – Pop-up


Embedded User Manual – Provides Detailed Guidance

Rodel InputsRodel Inputs

Main Screen – Error Messages


Main Screen – Error Messages (Same in HCM Model)


Main Screen – Warning Messages


© 2015 Rodel Interactive

Thank you!Live Demo

With Available Time

Insert the title of your presentation here Presented by Name Here Job Title - Date

ARCADY Roundabout Analysis Tool James Bedingfeld

11 June 2015

Table of contents

Page 2

Background and theory of ARCADY

Critical inputs for utilising ARCADY software

Step-by-step guide for data input

Output facilities

Analysis of the outputs

1

2

3

4

5

Background of Capacity Models

Page 3

o Capacity models based on research undertaken throughout last 40 years.

o The capacity equations were derived from extensive research into effects of various junction parameters.

o Empirical formula is used to calculate capacity as a function of geometry and traffic flows.

o Formulae themselves based on results of studying large number of real junctions and carrying out best-fit regression analysis

Background of Capacity Models

Page 4

o TRL undertook the capacity relationship of modern roundabouts in the UK during the 70’s and 80’s.

86 roundabout entries studied

11,000 minutes of capacity operation recorded

500,000 vehicles observed

o Reviewed these relationships in mid 1990’s to ensure appropriateness of the model.

o Managed contract to develop capacity relationships for large / grade separated roundabouts and mini-roundabouts.

Capacity Models within ARCADY

Page 5

o Normal / standard roundabout capacity model

o Large / grade separated roundabouts o UK style mini-roundabouts

o HCM 2010 roundabout capacity model

o HCM AWSC and TWSC included in ARCADY 9 to allow

direct comparison for alternative intersection configurations

o Lane Simulation to model various lane configurations / movements

Principles of the program

Page 6

o Single island at-grade normal roundabouts o Large and Grade-separated o Mini-roundabouts o 2-20 arms o Linked roundabouts o Entry lane simulation

ARCADY junctions that can be modelled


Page 7

o The program uses empirical formulae to calculate the capacity of each entry arm as a function of the geometry and the circulating flow crossing in front of the entry.

o For standard roundabouts, this is formulated as:

Qe = Fi - fi Qc

Entering flow, Qe

Circulating flow, Qc (Controlling flow)

F0

Intercept

CAPACITY - Two dimensional

Relationship is...

Qe = F0 - A1Qc Qe

Qc


Page 9

o Another basic feature of ARCADY is the way in which flows from individual arms of a roundabout are linked.

o ARCADY predicts capacity as a function of flow and geometries.

o For a basic ARCADY assessment the critical inputs are:

Six geometric parameters

Demand for each leg

Turning proportions for each leg

o On completion of the measurements setting up a basic file within the software can take no longer than 10 to 15 minutes

Critical inputs for utilising ARCADY software

Critical Inputs – Vehicle Demand

Page 11

o One of the two main components for determining capacity is traffic flow.

o Essential therefore that accurate traffic counts, or predictions, of Demand and Turning Movements occur.

o Demand data is the traffic flow that demands entry on an approach during a specific time period (whether 15 minutes, 1 hour etc).

o When measuring demand this should be at a point further upstream from the intersection than the maximum queue encountered.


Page 12

1. ‘DIRECT’ direct data for all arms 2. ‘LEVELS’ pre-peak, peak and post-peak flow levels 3. ‘FOUR’ 4 consecutive hourly

counts

4. ‘ONE HOUR’ One hour's peak flow usually as O-D table

5. PHF normal”, symmetric profile, fixed spread but peak may vary

6. Flat Flat profile based on a single number

both can vary in time and from arm to arm

turning proportions may be:

• specified directly or

• obtained from entry and exit flows (Furness Balancing) or

• implicit (from O-D matrix)


Critical Inputs ARCADY Major Geometric Parameters

Approach width (v)

B

A

F’

G

D

BD

2

Flare length (l’)

Page 14

Critical Inputs - ARCADY Minor geometric parameters

ENTRY RADIUS, r

INSCRIBED CIRCLE DIAMETER, D (ICD)= 2 x R

Radius , R

ENTRY (CONFLICT) ANGLE, Phi

φ

Page 15

Step-by-step guide for data input - Starting a New File

Page 16

Data Outline Diagram

Step-by-step guide for data input - Starting a New File

Step-by-step guide for data input - Developing a basic file

Step 1

File Description:

Access via Data Outline

Enter job details such as location, client, job number etc

Page 18


Step 2

Analysis Sets


Adding new / Copying exiting Analysis Set

Page 19

Step 3

Demand Sets


Adding new / Copying exiting Demand Set

Page 20


Step 4

Set Units Access via Data>Units

Page 21


Step 5 – A to C

Follow vertical tool bar

Page 22


Step 5 – D to E

Follow vertical horizontal tool bar

Page 23


Step 6

Run the file and view results

Page 24


Output facilities - Accuracy and reliability of Results

Page 25

oThe accuracy of the results from the program will reflect the accuracy of the input.

oFor a given capacity, the queue-length and delay predictions are the average values of broad distributions.

oWhere possible, the accuracy of the capacity and delay calculations for an existing junction may be improved by use of local traffic observations

oUse of the Analyser Screen will be of value to the user who is concerned with the robustness of a particular design.

oUse of the program should in general be limited to situations in which the values of the parameters involved lie within the range of values over which the relationships used have been calibrated.

Output facilities - ARCADY Reports

Page 26

o Report Generator Customisable Built-in HTML Viewer (or view in any web browser) Can save as PDF or convert to a Microsoft Word file Sorting/grouping options Report is always up-to-date (automatically runs file)

o File Comparison system ARCADY lets you work with multiple files simultaneously Can compare inputs and outputs Differences between files/ results highlighted as a report

Output facilities - Residual Capacity Mode

Page 27

o ARCADY can assess the network’s Residual Capacity.

o This is a measure of how much more traffic the system can cope with before a user-defined threshold is reached .

o If the system is already overcapacity, then the residual capacity indicates by how much the traffic would need to be reduced to restore satisfactory operation.

Output facilities - Working with Results

Page 28

Results are generated when you run a file. There are several types of results, including:

o Results for each leg for each time segment (e.g. delay on leg 1 for time-segment ending 08:15)

o Results for each leg for the whole modelled period (e.g. average delay on leg 1 for 08:00-09:00)

o Results for all legs added together – these are available via the automatically totaling in Data Grid screens.

o Summary results for each Analysis/Demand set, shown in the Summary Results screen.

Analysis of the outputs - Junction Diagram Screen

Page 29

Analysis of the outputs - Junction Diagram Screen – Queue overlays

Page 30

Analysis of the outputs – Printing, copying and exporting

Page 31

Analysis of the outputs – Analyser

Page 32

Analysis of the outputs – Optimiser

Page 33

o Enter a set of variables E.g. entry width and flare length on all arms Enter a range for each item

o Enter a set of targets E.g. VC on all arms < 0.85

o Press ‘Go’ Program will attempt to find values for the input items that satisfy the requirements (Not always possible!)

Calibration

Page 34

• Never been attempt in UK to drive national / regional correction – ALWAYS SITE SPECIFIC

• Application of intercept correction – Adjustment made based on observed capacity, alters position of Qe.

• May be possible to derive regional / national factor based on average of many sites.

• Capacity adjustment can be made scales leg or intersection based on observations.

• Capacity adjustment can be made to take into account any effect, no matter how complex the intersection but is based in engineering judgement.

ARCADY Roundabout Entry Lane Analysis mode

A

B

C

Page 35

ARCADY Roundabout Entry Lane Analysis mode

Page 36

Linking of junctions

Page 37

o Roundabouts are modelled jointly with the program performing all calculations

o It will model the affects of blocking back on upstream arms and transfer queues

o A ‘network’ of roundabouts can be modelled (queues may not be transferred due to exit restriction limitation)

o Any combination of roundabout types can be modelled

o It is easy to set up

o More time and cost efficient

Other notable features

Page 38

o Bypass lanes and filter lanes

o Application of exit restrictions

o Ability to apply National / Regional calibration values

o Ability to personalize window layouts to suit user needs

o Audit trail

o Reading of demand data from excel

o Link to Autodesk JUNCTIONS, build roundabout in CAD and link to ARCADY updates results.

o Ability to predict probability of reaching user defined queue marker

o Ability to predict geometric delay

o Ability to predict safety (based on UK accident research)

1. Introductiononlinepubs.trb.org/onlinepubs/webinars/150611.pdf · o HCM and Rodel both utilize...

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Transcript of 1. Introductiononlinepubs.trb.org/onlinepubs/webinars/150611.pdf · o HCM and Rodel both utilize...