STOPS (Simplified Trips-on-Project Software)

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Simplified Trips-on-Project Software
Vendor FTA
Data Input GTFS, CTPP, GIS shapefiles, travel time (.txt)
Data Output ridership projections, VMT changes

The FTA released STOPS in 2013 to help agencies adapt to the new Final Rule on major capitol investment projects approved through New Starts and Small Starts. These cover many fixed guideway transit projects around the country. The rule specifies that applications for these projects require ridership forecasts for new lines, since mobility benefits are evaluated as new trips on the project, with a double weight given to transit dependent users[1]. A component of the environmental benefit that is evaluated in the creation of a new line will includes changes to vehicle miles traveled (VMT). STOPS provides this information to help agencies offer it as part of their application for funding.

How it works

Four-step travel model

STOPS uses an altered four-step travel model to produce ridership and VMT estimates using zone-to-zone markets stratified by household vehicle ownership and a conventional mode-choice model to predict zone-to-zone transit travel.

Stops differs from four-steps models in a number of key ways:


  • STOPS factors the worker flows to represent home-based work-trip patterns and to account for home-based non-work-trip patterns as well.
  • STOPS uses the transit trip attractions predicted in each zone for home-based travel to characterize the non-home-based travel market.
  • Trip patterns are scaled to different years using population and employment estimates.
  • Coded transit data is replaced with GTFS both for the current transit system and to represent proposed changes.
  • STOPS relies on zone-to-zone roadway times and distances derived from the regional travel model for both the current year and for future predictions. This takes the place of any direct representation of the roadway network or directly assigned automobile trips.
  • VMT changes are calculated by multiplying trips shifted from automobile to transit on a zone-to-zone basis by the specified zone-to-zone travel distance.
  • STOPS is calibrated for broad application, not for any specific region, as four-step models often are. STOPS adjusts to specific regions in application by calibrating based on:
    • total transit system boardings;
    • the share of CTPP worker flows to jobs in each subarea that is captured by transit; and,
    • daily number of boardings at individual stations on any existing fixed-guideway facilities.


Project staff can download STOPS from the FTA website and install it locally.


STOPS uses a number of inputs for to make its predictions. Some are pulled directly through the software, whereas others have to be added by the project technician.

  • Census Transportation Planning Products (CTPP) can be downloaded as a state bundle from the STOPS page on the FTA website.[2]. This data provides population data, workflows, household automobile ownership, and mode-choice by zone.
  • GTFS data is provided by the local agency.
  • Zone-specific population and employment estimates for the year 2000, the current year and, if applicable, for one or more future years is pulled from the regional travel model.
  • Zone-to-zone roadway travel times and distances are pulled from the regional travel model.



STOPS use of standardized data such as GTFS and CTPP makes it much easier to maintain consistency and therefore offer effective predictions across different metros. This is particularly true when metro specific adjustments are made. A comparison of STOPS predictions and observed ridership on 15 different systems found a near perfect match.[3]

STOPS is particularly helpful where regional models are not available because they do not adequately represent transit as differentiated from road usage. Even where regional models are available, STOPS offers a useful quality control option to view a second ridership forecast, and the FTA will always accept the numbers derived from a successful application of STOPS.


  • STOPS is only available for evaluation of fixed guideway projects (because New Starts and Small Starts are only available for fixed guideway projects). It does not work for local buses or other roadway forecasts.
  • The CTPP data that STOPS relies on only offers routine weekday travel information, which looks at resident travel patters in the trip categories: home-based work, home-based non-work, and non-home based. This excludes special markets such as students or airport trips.
  • STOPS does not consider transit capacity. It does not adjust ridership forecasts based on limited capacity, and does not account for the benefits that a project can offer in relieving over-stressed transit capacity.
  • As of 2013, STOPS was using projections from CTPP info that was pulled from the 2000 census. There is a planned update to use ACS data to make it more current.


Further Reading