Considerations when applying Paramics to Strategic Traffic Models Paramics User Group Meeting

www.braidwoodassoc.com

Considerations when applying Paramics to Strategic Traffic ModelsConsiderations when applying Paramics to Strategic Traffic Models

Paramics User Group Meeting

October 9th, 2009

Presented

Matthew Juckes


Who We Are

Scotland, New Jersey, California offices

Consultancy

Project Audits/Peer Review /

Training

Paramics Training given to Caltrans, NYSDOT, NYCDOT, WISDOT

and many others

British Chamber of Commerce - International Business Award 2009


IntroductionIntroduction

Strategic Model Example – I-405 District 12Strategic Model Example – I-405 District 12

Study AreaStudy Area

Network InformationNetwork Information

OD Matrix InformationOD Matrix Information

ConsiderationsConsiderations

Project ScopeProject Scope

OD DevelopmentOD Development

Simulation SpeedSimulation Speed

Software EnhancementsSoftware Enhancements

Actuated SignalsActuated Signals

Freeway MOEFreeway MOE

Ramp MeteringRamp Metering

HOV Lanes; andHOV Lanes; and

HOT LanesHOT Lanes

Output StatisticsOutput Statistics

ConclusionsConclusions


Study Area Study Area A 25.4 -mile segment of the I-405) from the Los Angeles/Orange County Line to the I-405/ I-5 Interchange. A 25.4 -mile segment of the I-405) from the Los Angeles/Orange County Line to the I-405/ I-5 Interchange.

I-405 traverses an area with several key traffic generators and has freeway to freeway interchanges with the I-405 traverses an area with several key traffic generators and has freeway to freeway interchanges with the SR-73, SR55, SR-133 and I-5SR-73, SR55, SR-133 and I-5


I-405 – Los Angeles/Orange County Line and I-405/ I-5 Interchange

25.4 Miles

AM Period 06:00 – 10:00 (1 hour warm up period)

PM Period 15:00 - 19:00 (1 hour warm up period)

3896 Links

114 Zones

49 Ramp Meters (SATMS)

7 Freeway to Freeway Interchanges (I-605, SR-22 (two times) , SR-73, SR-55, SR-133 and I-5 )

Gradients and grade separations Modelled

I-405 Base Model InformationI-405 Base Model Information


PEMS Base Mainline Data


Matrix Totals

I-405 AM Trip Matrix – 568,527 vehicles

I-405 PM Trip Matrix – 639,594 vehicles


Matrix DevelopmentMatrix Development

Trip matrices have been developed for Trip matrices have been developed for all vehicle types. These have been entered in 2 all vehicle types. These have been entered in 2 matrix levels corresponding to the Single Occupancy Vehicles (SOV) and the High matrix levels corresponding to the Single Occupancy Vehicles (SOV) and the High Occupancy Vehicles (HOV).Occupancy Vehicles (HOV).

A three-stage process has been used to develop the AM and PM peak hour trip matrices A three-stage process has been used to develop the AM and PM peak hour trip matrices for both the for both the SR-22SR-22 and and I-405I-405 models; models;

The original strategic model (OCTAM Model) was cordoned to produce an AM and The original strategic model (OCTAM Model) was cordoned to produce an AM and PM demand matrices.PM demand matrices.

Infill for unobserved trips. Generations were estimated from each zone and Infill for unobserved trips. Generations were estimated from each zone and distributed to other internal zones; these infill trips were predominantly applied to distributed to other internal zones; these infill trips were predominantly applied to match the internal turning movements.match the internal turning movements.

The matrices produced at the end of the above steps were then used as the input The matrices produced at the end of the above steps were then used as the input (pattern) matrices for the Paramics matrix estimation procedure. In essence this (pattern) matrices for the Paramics matrix estimation procedure. In essence this ME procedure uses link and turn counts to control changes to the matrix totals and ME procedure uses link and turn counts to control changes to the matrix totals and trip distribution. trip distribution.


What is the aim of the project? Is it to consider mainline operation, arterial operation or both?

Is traffic data comprehensive? Is it comprehensive enough to achieve the aims of the project?

What are the key routes and intersections?

What is the model time period?

timescales/deadline – is it possible to deliver the project in the timescales? Large strategic models can be challenging to calibrate.

Are the software functionalities suitable/relevant to the project?

Project Scope


Default Time Steps - 2 Steps per Second

Increasing time steps will increase mean headway; and

Increases simulation time (and therefore project costs)

Think how many times model is run during Calibration

300-400 times, 300X30 (min) = 9000min/60 = 150 hours / 8 = 19 days = roughly an extra month of work

Simulation Speed

2 Time Steps 3 Time Steps 4 Time Steps

Time Taken (Hours:Minutes) 0 hours 56 minutes 1 hour 10 minutes 1 hour 29 minutesTime Taken (Minutes) 56 70 89

Percentage Difference - 25% 59%

Machine Specs: I ntel(R) Xeon(R) CPU; X5460 @ 3.16GHZ with 3.00 GB of RAM Running Windows XP


Traffic Signals – Actuated/Fixed

Ramp Metering – Fixed/SATMS/TOS/Alinea

HOV Lanes – weaving/non weaving; and

HOT Lanes

What are the potential disbenefits using external software enhancements?

Reduced simulation speed

Model instability; and

Model complexity.

Software Enhancements


Fixed Time vs Actuated Signals

Fixed Time

Plus – Standard GUI, easy to create;

Minus – Does not always match real world conditions;

Actuated Signals

Plus – Better match of real world conditions

- Greater signal capacity

Minus – Requires using VA script or API

Can be very time consuming and the final result is almost never perfect


Ramp Metering – Fixed/SATMS/TOS/Alinea

Fixed – Not a perfect situation but quick and easy;

Actuated simple – Simple call detection;

SATMS – Semi Actuated Traffic Metering System Requires API demand-capacity based traffic responsive control or Fixed time

TOS – I-880 – CALTRANS Requires API

Alinea - local feedback ramp-metering strategy Requires API Some concern on the use of Downstream Volumes


HOV Lanes – weaving/non weaving

Separated links vs Restrictions with rules/API Depends on goals of the projects and scenarios

HOT Lanes

Newly available function within paramics

Variable Cost Lanes

Dynamic link rules


What are the potential impacts to using external software enhancements?

Reduced simulation speed;

Model instability;

Model complexity;

Model technical support;

Multiple layering effect

Miss use of Plugin

Over use of Plugins


Modelled Link Counts

Example: I-405 AM Northbound

Modelled Turning Counts

Example: I-405 AM

Travel Times

Individual vehicle travel times, mean, max and minimum

Is a comparison between modelled and surveyed travel times possible?

Speedplots – data output, what is being compared.

Visuals

Example

Output Statistics


Macro – Micro Iterations

In a perfect world no manual adjustment needed

Regional Model

(Macro)

Sub-Area Macro Model

Micro-Model

Trip Table

Manual Adjustments

Final Model

Link and Node MOEs

Re-Run Macro with Micro MOEs as new input


Link Count ExampleLink Count Example

131 Turn Counts in I-405 Model 131 Turn Counts in I-405 Model >85% GEH < 5.0 for each hour>85% GEH < 5.0 for each hour


Turn Count ExampleTurn Count Example

149 Turn Counts in I-405 Model 149 Turn Counts in I-405 Model >85% GEH < 5.0 for each hour>85% GEH < 5.0 for each hour


Travel Times

Individual vehicle travel times, mean, max and minimum

Is a comparison between modelled and surveyed travel times possible?

0

50

100

150

200

250

300

350

400

450

Tra

ve

l Tim

e (S

eco

nd

s)

Intersection / Off Ramp

I -405 NB PM J ourney Time Modeled Vs Observed (16:00-17:00)

Observed J ourney Time Modeled J ourney Time


Speedplot ExampleSpeedplot Example

0.37 0.37 (0.6) -

0.88 0.88 (1.11) -

1.7 1.7 (1.9) -

2.66 2.66 (2.89) -

3.08 3.08 (3.31) -

3.8 3.8 (4.03) -

4.82 4.82 (5.05) -

5.51 5.51 (5.74) -

6.62 6.62 (6.85) -

7.5 7.5 (7.73) -

8.17 8.17 (8.4) -

8.67 8.67 (8.9) -

9.23 9.23 (9.46) -

9.67 9.67 (9.9) -

10.67 10.67 (10.9) -

11.37 11.37 (11.6) -

12.62 12.62 (12.85) -

13.51 13.51 (13.74) -

14.31 14.31 (14.54) -

14.94 14.94 (15.17) -

15.64 15.64 (15.87) -

16.53 16.53 (16.76) -

17.69 17.69 (17.92) -

19.01 19.01 (19.24) -

20.1 20.1 (20.33) -

21.33 21.33 (21.56) -

22.32 22.32 (22.55) -

23.39 23.39 (23.62) -

23.89 23.89 (24.12) -

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NB Base Model PM Speed Plot 080709v1

65-75

55-65

45-55

35-45

25-35

15-25

5-15


Visuals

Screenshots

3D PMX models

When is it worth developing a detail 3D background for your model?

Google Sketchup – User friendly free PMX designer

Videos – I-880 Example


FHWA Guidelines

Bottlenecks

Counts

Travel Times

Does the order that these are validated in really matter?

Sometimes something has to give…


For Further InformationFor Further Information

Richard Braidwood Richard Braidwood

[email protected]@braidwoodassoc.com

(213) 784 0889(213) 784 0889

or

Matthew JuckesMatthew Juckes

(732) 587 5786(732) 587 5786

[email protected]@braidwoodassoc.com

www.braidwoodassoc.comwww.braidwoodassoc.com

Considerations when applying Paramics to Strategic Traffic Models Paramics User Group Meeting

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