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Office of Transportation EPA420-F-05-046 

and Air Quality October 2005 

Program

Announcement 

EPA Releases New Guidance for 

Quantifying and Using Emission

Reductions from Best Workplaces for

Commuters Programs in State

Implementation Plans and

Transportation Conformity

Determinations 

The U.S. Environmental Protection Agency (EPA) has developed 

guidance for states and agencies that are involved in developing state 

implementation plans (SIPs) or transportation conformity determinations. 

This guidance explains how these agencies can incorporate emissions 

reductions resulting from changes in commuter trip behavior to their SIPs 

and transportation conformity determinations. 

The guidance explains how providing a high level of commuter benefits, 

as defined by achievement of the Best Workplaces for CommutersSM 

(BWC) designation, can result in decreased commuter trips, leading to 

decreased emissions. It also provides information on using one of the 

tools available to quantify these reductions—a newly-revised, 

spreadsheet-based calculator called the COMMUTER model. 

Best Workplaces for CommutersSM 

BWC is one of the voluntary programs offered by EPA’s Office of Transportation and Air Quality aimed at achieving measurable environmental 
benefits in a cost-effective way, without the need for regulation. Employers qualifying to be designated as BWC must offer excellent commuter 

benefits that meet the program’s “National Standard of Excellence.” 

Voluntary programs like BWC can reduce pollution and improve air 

quality through strategic partnerships with small and large businesses, 

citizen groups, industry, manufacturers, trade associations, and state and 

local governments. 

SIP and Transportation Conformity Determinations 

Commuter benefit programs like BWC can offer quantifiable emission 

reductions. The guidance document describes the requirements for 

seeking emissions credit for BWC-related measures in SIPs and transportation conformity determinations. While various modeling methodologies for estimating the benefits of BWC-related measures are available, 

state and local agencies seeking reductions for SIPs or conformity should 

engage in a consultation process with EPA regarding appropriate methodologies. 

COMMUTER Model 

EPA has updated the COMMUTER model, first released in 2001, to 

assist worksite transportation coordinators and local planners in estimating the impacts of commuter programs like BWC. The 2005 revision 

interfaces with EPA’s current MOBILE6.2 emission factor model and 

adds the capacity to estimate how a commuter benefit can impact particulate matter, air toxics emissions, and fuel use and costs. Running the 

model requires the user to provide information on the number of employees covered and the types of benefits offered to them. The COMMUTER 

model allows users to input local-specific travel data, and emissions 

factors based on a MOBILE6.2 run representing the area. The MOBILE6.2 look-up tables for emission factors in the COMMUTER model 

can be used to provide a preliminary estimate on what reductions are 

produced. If you choose to use the COMMUTER model to quantify 

emission reductions for SIP or transportation conformity purposes, you 

should use your own locally-generated MOBILE6.2 emission factors and 

local travel activity data to calculate emission reductions. 

Bundled Measures 

The guidance “Incorporating Bundled Measures in a State Implementation Plan (SIP)” released in August 2005 describes an option for how 

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BWC-related activities could be “bundled” with other voluntary measures for SIP purposes. In cases where many small employers in an area 

are implementing BWC-related activities, it may be appropriate to 

consult this guidance along with the Bundled Measures guidance to 

quantify and account for the expected emission reductions. 

For More Information 

You can access the guidance, the COMMUTER model, and related 

documents on the Office of Transportation and Air Quality (OTAQ) Web 

site at: www.epa.gov/otaq/transp/conform/policy.htm 

For questions regarding this guidance: 

Mary Walsh 

734-214-4205 

walsh.mary@epa.gov 

For questions regarding BWC measures in transportation conformity 

determinations: 

Meg Patulski 

734-214-4842 

patulski.meg@epa.gov 

For questions regarding the COMMUTER model: 

Erik Herzog 

734-214-4487 

herzog.erik@epa.gov 

For more information about Best Workplaces for CommutersSM, visit the 

Web site at www.bwc.gov, send an e-mail message to bwc@epa.gov, or 

call the Best Workplaces for CommutersSM information line at 1-888-

856-3131. 

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