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Model Report


Last Revision Date: 12/02/2011 View as PDF
General Information Back to Top
Model Abbreviated Name:

Model Extended Name:

Model Overview/Abstract:
The Commuter model is a spreadsheet based software program that analyzes the vehicle-trip reduction effects of a wide range of travel demand management strategies related to commuting. It can used to estimate the travel and emissions impacts of pricing and subsidy incentives, transit improvement, carpooling and vanpooling promotion; and telecommute and work hour strategies.

It is designed to be usable by people with basic computer skills who do not necessarily have experience with models. Commuter offers two levels of analysis: Regional analyses can be done on programs covering an urban area, a central business district or a highly-traveled corridor. Site- specific analyses enable benefits to be projected for programs at individual worksites.

Data requirements include the number of people affected, baseline mode shares, trip lengths by mode, and description of the program implemented, including changes in travel time or cost. Gasoline price is an optional input. The user has the option to change default parameters affecting strategy effectiveness.

The model is based on the pivot point methodology used in FHWA's TDM Evaluation Model. Strategies that affect the time and/or cost of travel are evaluated using a "pivot-point" mode choice model. The pivot point model is a derivative of the logit mode choice model commonly used in four-step travel demand models.

Model output includes changes in modal share, vehicle-trips, and vehicle miles traveled, and the resulting emission reductions of hydrocarbons, carbon monoxide, nitrogen oxides, particulates, and carbon dioxide. It also calculates reductions in gasoline usage and total fuel cost savings. Emission reductions are based on the calculated changes in trips and VMT, using lookup tables derived from MOBILE6.

Keywords: transportation demand management (TDM), transportation, control measures (TCMs), commuter benefits, commuter choice, commute alternatives, vehicle miles traveled (VMT) reduction, transit benefits, ridesharing, teleworking, telecommuting, parking cash out, State Implementation Plans (SIPs), transportation, conformity, ozone action days, episodic control measures, seasonal measures
Model Technical Contact Information:
EPA Contact:
Erik Herzog
Office of Air and Radiation
Office of Transportation and Air Quality

Developer Contact:
Christopher Porter
Cambridge Systematics, Inc.

Model Homepage: http://www.epa.gov/otaq/stateresources/policy/pag_transp.htm#cp

User Information Back to Top
Technical Requirements
Computer Hardware
Pentium CPU with 150 MHz minimum 2.0 MB disk space for the model plus 47.4 MB disk space for external emission factor look-up files, 40 MB needed for user-generated MOBILE6 emission factors, if used
Compatible Operating Systems
Windows 95 or later
Other Software Required to Run the Model
Visual Basic for Microsoft Excel
Download Information
The Commuter model is publicly available to be downloaded.
Using the Model
Basic Model Inputs
• Type of analysis (site-specific or are-wide) • Metro area size (select small, medium or large)
  • Types of and amounts of incentives
  • Starting travel mode shares and average trip distances
  • Analysis year
  • Other Mobile Source control programs (I/M, fuels0
  • Fleet mix by vehicle type
  • Gasoline price (optional)
Basic Model Outputs
  • Ending travel mode shares resulting from incentives
  • Vehicle Miles Traveled (VMT) reduced
  • Trips reduced
  • Pollutants reduced – HC, CO, NOx, CO2, PM, and some air toxics
  • Gasoline Saved
  • Money saved on gasoline (if fuel price is provided)
User Support
User's Guide Available?
A user's manual, and a manual describing the analytical procedures are available to be downloaded.
Availability of User Support
Users can call the EPA Contact with questions
User Qualifications
The user needs some knowledge of alternative commute incentive programs but deep expertise is not required. First year employee or intern with basic competency in MS Excel and Windows programs could use it successfully.

Model Science Back to Top
Problem Identification
In course of developing our Voluntary Measures SIP policy, the need became evident for a modeling tool that individuals involved in planning and implementing alternative who were not expert in travel demand modeling could use, or that could be used for sketch planning purposes.
Summary of Model Structure and Methods
Incentives are divided into two types: those that affect the time and/or cost of travel by mode, and those that provide information or encouragement for alternative commute modes. Travel modes are adjusted to account for incentives involving information and encouragement based upon results of research. Incentives affecting time and cost are analyzed using a pivot point methodology to determine how they change the relative attractiveness of travel modes. Changes and trips and VMT are calculated from the changes in mode share, and emissions and fuel use changes are calculated from changes in trips and VMT based on look-up tables of runs of the MOBILE6 model.
Model Evaluation
The model has been peer reviewed by a Federal Advisory Committee workgroup. In addition, the Chicago Area Transit Study (CATS), the Metropolitan Planning Organization for the Chicago area, compared the Commuter Model with the TDM Model by running a number of scenarios for the Chicago area and found the results to be in reasonably close agreement on both models.

Key Limitations to Model Scope
The model works best when analyzing impacts at the site-specific level, i.e., a single workplace or office park where a single set of incetives is offered to all commuters. Area-wide analyses, in different incentives are available to different commuters are best done on a small geographic scale. Because it does not employ trip tables, the results may be inaccurate if applied to an entire county or metro area.
Case Studies
Hillsborough County Long Range TDM Plan and the Pinellas County Long Range TDM Plan
Under contract to Bay Area Commuter Services, Inc., CUTR analyzed several scenarios of transportation demand management (TDM) strategies to provide assessment of each scenario in the Year 2025. This information provided input on the role and needs of TDM programs to be addressed in each MPO's Long Range Transportation Plan for the Year 2025. The project identified the key measures of effectiveness (i.e., vehicle miles of travel, vehicle trips, mode split, and emissions) for assessing the impact of TDM in each county; reviewed each county's 2020 Long Range Transportation and Comprehensive Plans; reviewed similar plans from five peer communities to identify approaches used by those communities; identified strategies for analysis at several levels: countywide, activity centers and employer site level. An analysis was conducted using the Environmental Protection Agency’s COMMUTER Model to assess effects of different combinations of TDM strategies on the key measures of effectiveness. These strategies were identified by the Advisory Committee and grouped into four scenarios. The potential policies and/or program changes related to, but were not limited to, a comprehensive employer outreach program, the provision of transit and vanpool benefits by employers, planned improvements to transit system, and growth in the adoption of compressed work week and telecommuting programs by employers. Analyses for several major activity centers within each county also were conducted. Report includes impacts on performance measures and estimated costs for various programs.

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