Considerations when applying Paramics to Strategic Traffic Models
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Considerations when applying Paramics to Strategic Traffic Models Paramics User Group Meeting October 9 th , 2009 Presented Matthew Juckes. Who We Are Scotland, New Jersey, California offices Consultancy Project Audits/Peer Review / Training

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Considerations when applying paramics to strategic traffic models paramics user group meeting

Considerations when applying Paramics to Strategic Traffic Models

Paramics User Group Meeting

October 9th, 2009

Presented

Matthew Juckes


Considerations when applying paramics to strategic traffic models paramics user group meeting

  • Who We Are Models

    • 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


Considerations when applying paramics to strategic traffic models paramics user group meeting

  • Introduction Models

  • Strategic Model Example – I-405 District 12

    • Study Area

    • Network Information

    • OD Matrix Information

  • Considerations

    • Project Scope

    • OD Development

    • Simulation Speed

    • Software Enhancements

      • Actuated Signals

      • Freeway MOE

      • Ramp Metering

      • HOV Lanes; and

      • HOT Lanes

    • Output Statistics

  • Conclusions


Study area
Study Area Models

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 SR-73, SR55, SR-133 and I-5


Considerations when applying paramics to strategic traffic models paramics user group meeting

I-405 Base Model Information Models

  • 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



Matrix totals
Matrix Totals Models

I-405 AM Trip Matrix – 568,527 vehicles

I-405 PM Trip Matrix – 639,594 vehicles


Matrix development
Matrix Development Models

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

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

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

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

    • 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 ME procedure uses link and turn counts to control changes to the matrix totals and trip distribution.


Considerations when applying paramics to strategic traffic models paramics user group meeting

Project Scope Models

  • 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?


Considerations when applying paramics to strategic traffic models paramics user group meeting

Simulation Speed Models

  • 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


Considerations when applying paramics to strategic traffic models paramics user group meeting

Software Enhancements Models

  • 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.


Considerations when applying paramics to strategic traffic models paramics user group meeting

  • Fixed Time vs Actuated Signals Models

    • 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


Considerations when applying paramics to strategic traffic models paramics user group meeting

  • Ramp Metering – Fixed/SATMS/TOS/ ModelsAlinea

  • 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


  • Considerations when applying paramics to strategic traffic models paramics user group meeting

  • HOT Lanes

    • Newly available function within paramics

    • Variable Cost Lanes

    • Dynamic link rules


  • Considerations when applying paramics to strategic traffic models paramics user group meeting


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    Output Statistics enhancements?

    • 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


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    Regional Model

    (Macro)

    Sub-Area Macro Model

    Trip Table

    Micro-Model

    Re-Run Macro with Micro MOEs as new input

    Manual Adjustments

    Final Model

    Link and Node MOEs


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    Link Count Example enhancements?

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


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    Turn Count Example enhancements?

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


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    • Travel Times enhancements?

      • Individual vehicle travel times, mean, max and minimum

      • Is a comparison between modelled and surveyed travel times possible?


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    Speedplot enhancements? Example


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    • Visuals enhancements?

      • 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


    Considerations when applying paramics to strategic traffic models paramics user group meeting

    • FHWA Guidelines enhancements?

      • Bottlenecks

      • Counts

      • Travel Times

    • Does the order that these are validated in really matter?

    • Sometimes something has to give…


    For further information
    For Further Information enhancements?

    Richard Braidwood

    richard@braidwoodassoc.com

    (213) 784 0889

    or

    Matthew Juckes

    (732) 587 5786

    matt@braidwoodassoc.com

    www.braidwoodassoc.com