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    Transportation Forecasting: What Is It?

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    Tauseef
    Transportation forecasting uses a four-step model to estimate future travel demand: 1) Trip generation estimates the number of trips originating and ending in each zone based on socioeconomic data. 2) Trip distribution determines trip destinations from origins. 3) Mode choice identifies the transportation mode for each trip. 4) Route assignment specifies the actual routes for each trip. Trip generation models predict "trip ends," classified as origins/destinations or productions/attractions depending on land use, to estimate a zone's total trips. Residential zones produce trips while non-residential zones attract trips.

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    Transportation Forecasting: What Is It?

    Uploaded by

    Tauseef
    76 views8 pages
    Transportation forecasting uses a four-step model to estimate future travel demand: 1) Trip generation estimates the number of trips originating and ending in each zone based on socioeconomic data. 2) Trip distribution determines trip destinations from origins. 3) Mode choice identifies the transportation mode for each trip. 4) Route assignment specifies the actual routes for each trip. Trip generation models predict "trip ends," classified as origins/destinations or productions/attractions depending on land use, to estimate a zone's total trips. Residential zones produce trips while non-residential zones attract trips.

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    Transportation forecasting uses a four-step model to estimate future travel demand: 1) Trip generation estimates the number of trips originating and ending in each zone based on socioeconomic data. 2) Trip distribution determines trip destinations from origins. 3) Mode choice identifies the transportation mode for each trip. 4) Route assignment specifies the actual routes for each trip. Trip generation models predict "trip ends," classified as origins/destinations or productions/attractions depending on land use, to estimate a zone's total trips. Residential zones produce trips while non-residential zones attract trips.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
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    76 views8 pages

    Transportation Forecasting: What Is It?

    Uploaded by

    Tauseef
    Transportation forecasting uses a four-step model to estimate future travel demand: 1) Trip generation estimates the number of trips originating and ending in each zone based on socioeconomic data. 2) Trip distribution determines trip destinations from origins. 3) Mode choice identifies the transportation mode for each trip. 4) Route assignment specifies the actual routes for each trip. Trip generation models predict "trip ends," classified as origins/destinations or productions/attractions depending on land use, to estimate a zone's total trips. Residential zones produce trips while non-residential zones attract trips.

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    Transportation Forecasting

    What is it?

    Transportation Forecasting is used to estimate the


    number of travelers or vehicles that will use a given
    transportation facility in the future

    The conventional approach to transportation


    forecasting is based on what is commonly know as
    the ‘four step model’
    The Four Step Model

    • Trip Generation
    Estimates the number of trips from given origins and
    destinations
    • Trip Distribution
    Determines the destination for each trip from a given origin
    • Mode Choice
    Determines the mode choice for each trip
    • Route Assignment
    Determines the specific route for each trip
    Trip Generation

    Trip Generation model is used to estimate the number of person-trips that


    will begin or end in a given traffic analysis zone

    1
    3
    2 5

    4 8
    7
    6

    The unit of analysis for traffic generation is the TAZ


    Trip Generation Model

    Estimated
    Predicted
    Target year Calibrated
    Target year
    socio-economic, Model No. of Trips
    land use data
    Trip Generation
    What is Predicted?

    Trip generation models predict so called TRIP ENDS for each zone

    The trip ends maybe classified as either


    • ORIGINS and DESTINATIONS (O-D)

    or

    • PRODUCTIONS and ATTRACTIONS

    The two sets of terms sound similar but there is a technical difference
    Origins and Destinations
    Residential

    Non-residential

    8
    A worker leaves Zone 1 in the morning to Non-residential
    go to work in Zone 8
    Residential
    This results in 2 trip ends:
    • One Origin for Zone 1
    • One Destination for Zone 8
    Total Number of Trip Ends
    When that same worker leaves Zone 8 in
    the evening to go to home to Zone 1 Zone 1: 2 Trip Ends (1 O, 1 D)

    Zone 8: 2 Trip Ends (1 O, 1 D)


    This results in another 2 trip ends:
    • One Destination for Zone 1
    • One Origin for Zone 8
    Productions and Attractions
    Residential

    Non-residential

    8
    A worker leaves Zone 1 in the morning to Non-residential
    go to work in Zone 8
    Residential
    This results in 2 trip ends:
    • One Production for Zone 1
    • One Attraction for Zone 8
    Total Number of Trip Ends
    When that same worker leaves Zone 8 in
    the evening to go to home to Zone 1 Zone 1: 2 Trip Ends (2 Productions)

    Zone 8: 2 Trip Ends (2 Attractions)


    This results in another 2 trip ends:
    • One Production for Zone 1
    • One Attraction for Zone 8
    Origins and Destinations??
    Productions and Attractions??

    Based on the convention of trip generation models

    Origins and Destinations are defined in terms of the direction of


    the trip

    Productions and Attractions are defined by the land use

    Residential Land use PRODUCES trip ends


    Non-residential land use ATTRACTS trip ends

    This is a useful distinction because of how trip generation models


    are typically developed based on this.

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