TRIMMS™  (Trip Reduction Impacts of Mobility Management Strategies) was developed under a series of grants from the Florida Department of Transportation and the U.S. Department of Transportation.  TRIMMS is a visual basic (VB) application spreadsheet model that estimates the impacts of a broad range of transportation demand initiatives and provides program cost effectiveness assessment, such as net program benefit and benefit-to-cost ratio analysis.

TRIMMS evaluates strategies directly affecting the cost of travel, like public transportation subsidies, parking pricing, pay-as-you-go pricing, and other financial incentives.  Subsidies are provided to the employee by the employer to reduce the costs associated with the use of a particular method of commuting.  Subsidies can take different forms such as cash, discount passes, and vouchers.

TRIMMS also evaluates the impact of strategies affecting access and travel times and a host of employer-based program support strategies, such as: TDM program support initiatives, alternative work schedules, telework and flexible work hours, and worksite amenities.  TDM program support includes rideshare matching services, the provision of guaranteed ride home or emergency ride home for vanpool and carpool users; vanpool formation support; program promotion; and employee transportation coordinators.  Alternative work schedules include compressed work week, flexible working hours, and telecommuting. Worksite amenities include the provision of childcare facilities and the presence of sidewalks connecting transit stops within or nearby the worksite.

Starting from a baseline scenario describing a TDM program in terms of commuter travel behavior (mode shares, average trip lengths, peak and off-peak spreads), TRIMMS evaluates the impacts of TDM implementation by estimating changes in travel behavior (mode shares, VMT reductions).  Changes in the baseline scenario are then used to estimate changes in the external costs associated with these travel behavior changes.  Negative externalities arise whenever costs associated with single occupant vehicle (SOV) use, such as added congestion delay, air pollution, and increased accident risk, are not directly sustained by auto users but are rather imposed on the society as a whole.  TRIMMSestimates changes in costs for the following externalities:

  • Air pollution emissions.
  • Added congestion.
  • Excess fuel consumption.
  • Global climate change.
  • Health and safety.
  • Noise pollution.

I am currently developing a commercial website with interactive content and I am also working on a web version of TRIMMS.  For more information, please check or use the contact form below:

* indicates required field