Resource Information

EPA’s Guidance for Quantifying Emission 

Reductions from Best Workplaces 

for Commuters Programs for Use 

in State Implementation Plans and Transportation Conformity Determi

­

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

a guidance document for states and agencies that are involved in 

developing state implementation plans (SIPs) or transportation con­

formity determinations. This document, “Guidance for Quantifying 

Emission Reductions from Best Workplaces for Commuters Programs 

in State Implementation Plans and Transportation Conformity De­

terminations” (EPA420-8-07-015), explains how agencies can incor­

porate 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 ben­

efits, as defined by achievement of the Best Workplaces for Commuters 

(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, spread­

sheet-based calculator called the COMMUTER model. 

Best Workplaces for Commuters 

BWC, a voluntary program developed by EPA’s Office of Transportation and Air 

Quality and now administered by the Center for Urban Transportation Research, 

aims 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 

Office of Transportation and Air Quality 

EPA420-F-07-064 

October 2007 
Resource Information

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 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/stateresources/policy/pag_transp.htm 

For questions regarding this guidance: 

Mary Walsh 

734-214-4205 

walsh.mary@epa.gov 

Guidance for Quantifying and Using Emission Reductions 
Resource Information

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 Commuters, visit the Web site at 

www.bestworkplaces.org, or send an e-mail message to info@bestworkplaces.org. 

Guidance for Quantifying and Using Emission Reductions