Sierra Club logo

Stopping Sprawl campaign home page - click here.
Get an overview. Sign up for an e-newsletter. Find out what you can do to help.
Environmental Update Main
Sprawl Main
In This Section
Sprawl Overview
Reports & Factsheets
Activist Resources
Get Involved!
Articles & Research
Population and Sprawl

Get The Sierra Club Insider
Environmental news, green living tips, and ways to take action: Subscribe to the Sierra Club Insider!


Stop Sprawl
Cutting Commute Driving

An Environmental Tool Kit

Kate Bickert -- Rails to Trails Conservancy
Stuart Cohen -- Bay Area Transportation Choices Forum
James Corless -- Surface Transportation Policy Project
Tom Graff -- Environmental Defense Fund
John Holtzclaw -- Sierra Club

Association for Commuter Transportation
Annual International Conference
San Francisco, 31 August 1998

Motor vehicles are the single largest source of air pollution, especially in urban areas, and a major source of water pollution. In the San Francisco Bay Area, for instance, on-road vehicles emit 43% or the reactive organic gases and 47% of nitrogen oxides (BAAQMD 1997, Table 1). Nationally, motor vehicles emit 29% of volatile organic compounds, 31% of nitrogen oxides and 60% of carbon monoxide (EPA 1998, Table 5-1). Smoky exhausts, nitrogen oxides and entrained dust from motor vehicles are a substantial fraction of particulates, especially the harmful fine particulates (PM 2.5).

After leaving the assembly line auto emission systems deteriorate and must be maintained to keep emissions low. Yet legislators shy away from requiring more effective inspection and maintenance programs, such as centralized inspection, loaded-mode tests, higher mandatory repair limits and diesel standards, in all state non-attainment areas. Talk radio even raised a firestorm in San Francisco against cleaner-burning reformulated gasoline. Nor are evaporative emissions or entrained dust even addressed by tailpipe controls. There appear to be real political limits to more effectively cleaning up the car.

In 1987, highway fuel use, including diesel, in the U.S. contributed 309 million tons of carbon as CO2, or 370 million tons for the full fuel production and use cycle, which excludes construction of roads or production of vehicles (OECD 1993, Table 8). These comprise 22.4% and 26.9% of total U.S. fossil fuel emissions of CO2, the major global warming gas.

Yet, while most industrial sources of pollution are holding constant or declining, vehicle miles traveled (VMT) continues to grow. U.S. VMT grew at 1.7% percent per year between 1985 and 1995, and is forecast to increase 25 percent per capita between 1990 and 2010 (Davis 1987, Table 1.8; PCSD, 1996, p35). Reversal of these VMT increases is crucial to reducing pollution to healthy levels, to curbing global warming, and to creating a sustainable economy.

Why target commute driving?

Work commutes were 27% of all 1990 motor vehicle trips, and 28% of all miles driven in the U.S. (Davis 1997 Table 1.12). Over 90% of all driving commute miles are in single occupant vehicles, SOV (Davis 1997, Fig. 4.1). Most traffic congestion occurs during work commutes because they are concentrated in two short time periods a day. The start and go driving resulting from traffic congestion increases air pollution and fuel consumption. In addition, workers with on-site autos are more likely to drive to lunch or for other noontime trips.

However, reducing work commutes is only one way employers can help reduce motor vehicle mileage. Employers can educate employees about the alternatives to driving for other trips and their benefits, including improved air quality and more physical exercise. Employers can also educate employees about the impacts of the external costs of motor vehicle use and of sprawling land uses on work and other trips, and what employees can do to correct these imbalances. Employers can also work to improve public transit for work commutes and other trips.

Reducing work commute stress is a potential direct benefit to employers. Employees who have had a long, stressful commute are likely more tense and less able to concentrate on work. Their home-life can deteriorate due to such stresses, with unfortunate impacts on their work. Long stressful commutes through harmful air pollution can leave an employee groggy and require a period of rest before much useful work is possible. Air pollution can harm employees’ health, increasing worktime losses and medical costs to employees and employers.

Quicker work commutes leave more time for work. Walking, bicycling and public transit commutes can save employees money, with beneficial impacts on employee demands for compensation. Expensive nearby housing, and the long commutes it triggers, increases the difficulty and expense of hiring and keeping employees.

SOV reduction programs can also increase employee health and productivity. Walking and bicycle commutes increase employee exercise, improving employee health and alertness. Employees commuting by SOV in stop and go traffic while breathing toxic air are more likely to arrive irritable and groggy, and require recovery time. Those not driving should arrive fresher and be more productive.

SOV reduction programs can also raise employee morale and improve employee retention. They offer alternatives to employees frustrated by congestion and traffic hassles. Companies enthusiastically employing these programs have a hiring advantage. See sidebar for more information on employer and employee acceptance of parking cash-out.

Direct incentives to reduce single occupant vehicle commutes

Many firms are helping to improve alternatives to single occupant vehicle commuting and providing direct incentives to their employees to avoid it. These programs give employees more flexibility in commute decisions. Some of these programs are limited to a single company; others are a part of local or regional transportation demand management (TDM) programs. (Link to TDM resources) TDM programs include a wide variety of services, including rideshare matching, transit improvements, bicycle and pedestrian facility improvements, parking management, and promotion. These can provide significant financial savings to governments, businesses and consumers, as well as environmental benefits. Transportation management associations have been organized in some cities to provide services such as rideshare matching, transit information, and parking coordination in a commercial district or mall. This allows even small businesses to participate in commute trip reduction programs, and achieves more efficient use of resources.

Some of the most effective demand management strategies relate to righting the imbalance in incentives provided by free parking to employees. Free parking, subsidized by federal and state tax policies which allow the value of that parking to be tax-free both to employers and employees, provides a powerful incentive to drive alone. Eliminating free parking for employees and for customers and clients would provide a strong incentive not to drive and greatly benefit the environment. However, it would be unpopular with many employees and customers, and therefore difficult to get adopted and implemented. Consequently, environmentalists have also supported subsidies for the alternatives to driving. Three of the most promising of those, considering both their effectiveness and implementability, are listed below and described further in sidebars.

Parking cash-out. "Cashing out" means that employees who receive free parking are also offered a cash alternative equal to the value of a parking place if they commute by other modes. This typically reduces driving by 10-30%, and increases equity by giving non-drivers a benefit comparable in value to what drivers receive. Recent changes in federal law have removed the tax penalty on employees with free parking, enhancing PCO’s viability and value.

Bank of America’s BEAT. BoA’s non-SOV employees in the Los Angeles basin are rewarded with cash payments that vary according to the approximate environmental benefit of their modal choices. So a telecommuter gets $1.00/day, a carpooler $1.75, $2.00 or $2.25 depending on whether it is a 2, 3 or 4+ carpool, a vanpooler $2.50, a mass transit rider $2.75 and a walker or biker gets $3.00. These are paid out in 25 dollar increments with a BOA Debit Card, as described in sidebar. These cash payments can be applied to TransitChecks. The program is simple to administer since employees report their commutes monthly. Presently, the rewards are far below the value of the parking they are forgoing, but the environmentally-based sliding scale of rewards is a plus.

Commuter check subsidies for public transit and vanpools. With the passage of the Transportation Equity Act for the 21st Century (TEA 21), employers can provide tax-free employee transit or qualifying vanpool subsides of up to $65/month. These benefits are in lieu of existing salary, and are tax-free to both employee and employer. Many Santa Clara County employers have gone this one better by offering Eco Passes to their employees. Not only employees, but also their family members can use Eco Pass on weekends as well as workdays.

In addition to cash benefits to employees, there are many other incentives employers can provide to employees who walk, bike or take public transit. These include biking and pedestrian paths and access where necessary, secure bicycle parking and showers.

Since each of these programs reduces the employee parking needed, companies should be allowed to reduce the number of parking spaces provided. Local zoning laws which require minimum parking spaces should be reformed to allow employers who reduce employee driving to eliminate parking places and use the land for other purposes. Companies advocating reduced minimum parking requirements not only reap a direct economic benefit, but they also can improve urban land use.

Employer support for land use reforms

Many studies have shown that land use patterns strongly impact auto ownership and driving, described in sidebar. The more compact land use patterns reduce can reduce employee commute distances and stresses, improving employee performance and enhancing employee recruitment. So it is to employers’ benefit to facilitate compact, mixed-use, pedestrian- and bicycle-friendly development.

Employers can support development of compact, mixed-use, pedestrian- and bicycle-friendly areas by educating employees about the benefits of such development, facilitating neighborhood design charettes to plan zoning changes, giving time off from work to testify in support of such changes and development consistent with such changes, and by joining coalitions to reform zoning laws. The Silicon Valley Manufacturing Group has organized a Housing Action Coalition with over 200 organizations and individuals to provide support for construction of well-built, relatively affordable and appropriately located housing. Both the Coalition and the SVMG’s Housing Leadership Council include participation by environmental and housing activists. The goals of such coalitions should be to increase residential densities, zone residential areas to allow mixed uses, and to create pedestrian-, bicycle- and transit-friendly walkways and streets.

Increase residential densities. Since residential density is the single most important determinant of motor vehicle use, strategies to reduce global warming emissions from residences by increasing residential density also reduce motor vehicle use.

  • Eliminate front and side yard setback requirements in zoning ordinances.
  • Increase allowed building heights and floor-to-area ratios in zoning ordinances, especially near public transit centers and along public transit corridors. Zone for and encourage infill development on unused or underused land (empty lots, parking lots, abandoned buildings, service stations and brownfields--abandoned industrial land). Promote interesting diversity by including a variety of housing types, unit sizes, rents and prices. Site new development near transit, stores and services.
  • Bring neighborhood residents together with planning officials to evaluate the benefits of infill development, including walkable streets, nearby restaurants, stores, services and better public transit, and to decide where and how infill should occur in their neighborhood. Rezone based upon the results of these planning charettes. These changes support infill housing developers.
  • Bring back downtown living. Encourage apartment and condo development downtown.
  • Replace off-street parking minimums with off-street parking maximums in zoning ordinances, and severely restrict the ground coverage of any parking facilities.
  • Delink the purchase or rental of parking from the purchase or rental of apartments or condos so households can buy or rent housing without parking.
  • Legalize second, or "in-law" units, especially in single family areas in order to put basements, garages or unused rooms to use.
  • Provide adequate public parks and open space for nearby residents. Halt sprawl development on the periphery by establishing urban growth boundaries.
  • Include an air quality element in each city’s Comprehensive Plan.
  • Implement Location Efficient Mortgages. These allow households moving into dense, transit-served neighborhoods to qualify for a larger mortgage based upon their expected average saving from owning fewer cars and driving less than households moving into single family areas. If the expected auto savings is $500 per month, the household should qualify for a mortgage with $500 larger monthly housing payments. Location Efficient Mortgages are being developed in Chicago and other American cities.

Zone residential areas to allow mixed uses

This would allow jobs, markets, restaurants, video rentals and other neighborhood businesses in residential areas. In denser areas many of these would be mom and pop markets on residential streets. In less dense neighborhoods these businesses could be kept on major streets--but in the neighborhood, not stuck off in a shopping center 5 miles away, accessible only by freeway.

Create pedestrian-, bicycle- and transit-friendly walkways and streets

  • Create an efficient pedestrian street grid not broken by dead ends, freeways, fences or drainage ditches. The traditional rectilinear street grid, with short blocks, offers many alternative paths, allowing the walker to explore different streets, find favorites, and to link trips more easily. Winding streets, intersected by dead-ends and cul d' sacs require longer trips and allow no such variety.
  • Build sidewalks on both sides of all streets; with bus shelters, seating and other sidewalk furniture; trees, awnings and weather protection; and fountains, interesting store windows and other attractions.
  • Zone to locate building entrances near sidewalks so pedestrians need not walk through a parking lot or tread a long path.
  • Calm traffic so it is safe and slow, with drivers alert for pedestrians and children rather than intent on getting through the area speedily. Or at least protect sidewalks from traffic and install frequent stop signs and lights to allow safe street crossing. Traffic calming can help change the culture of neighborhoods and rekindle interest in pedestrian-friendly city living.

European cities have developed attractive street designs to alert motorists that people are likely to be walking, biking or playing, and that it is dangerous to drive hazardously (Zuckermann 1991). Sidewalks are widened and streets are narrowed to create a sense of closeness and activity. Cross-walk color and texture, perhaps brick or cobblestone, differs from that of the roadway. Speed humps and speed brakes alert drivers audibly as well as visually. Narrowing streets at the intersection or mid-block, single lanes of traffic or off-setting lanes caution the driver to slow down and pay attention. Stop signs, turn-movement prohibitions and posted speed limits slow traffic. Landscaping and benches further convey the sense of people strolling and children playing. Some roads are closed to divert or limit traffic. These neighborhoods convey a sense of being somewhere, rather than a place to pass through. Since autos are given less land, more is available for natural habitats, creeks and wildlife corridors.

Strictly limit highway capacity increases, and strategically reduce capacity in some areas.

Employer support for public transit and pricing reforms to counteract the external costs of private motor vehicle use.

Improve public transit service

Provide employees with parking cash-out, transit passes or other direct or indirect subsidies to public transit. Provide transit-only right-of-ways and rail service along major transit corridors and between major centers. Give public transit vehicles stop-light overrides. Coordinate public transit routing, schedules and fares. Improve pedestrian and bicycle access to public transit.

Counteract the external costs of private motor vehicle use

Americans’ external costs of driving (some call these subsidies) are equal to $3.00 to $7.00 for every gallon of gas consumed, according to six recent studies, see Table 1. Even when drivers bear these costs as a group, they are non-marginal (individual drivers do not pay in proportion to how much they drive), and so provide little incentive for efficient travel (Litman 1998-2). This is also inequitable, because it forces those who drive less than average (who tend to be lower income) to subsidize the vehicle costs of vehicle owners who drive more than average.

Fixed internal costs of motor vehicles are an equally significant problem. In particular, fixed vehicle insurance, registration fees, free residential parking, and relatively poor residential vehicle rental options represent "underpricing" that contributes about as much to vehicle overuse as do external costs (Litman 1998-2). It is also unfair because lower-mileage drivers end up subsidizing the vehicle costs of high-mileage drivers. While it is true that public transit is also subsidized, Miller and Moffet calculate that public transit external costs, or subsidies, about equal private motor vehicle external costs per passenger mile. Since private motor vehicle trips average 3 to 4 times longer than public transit trips, their external costs per trip are 3 to 4 times higher than those for public transit.

Employers can support implementation of least-cost (or "integrated") transportation planning and funding. Least-cost planning means that programs to reduce demand are considered equally with programs to increase capacity, that all significant impacts are considered, and that the public is involved in developing and evaluating alternatives. This ensures that demand management strategies receive appropriate consideration and investment (Litman 1998). These strategies include the following:

  • Reform state law to provide distance based-vehicle insurance and registration fees. Basing vehicle insurance and registration fees on distance traveled provides a significant financial incentive to reduce driving, and makes insurance premiums more fair and affordable. It would decrease vehicle travel by approximately 10%, reduce crash rates by a greater amount, increase equity, and save consumers money (Litman 1998).
  • Reform road pricing to directly charge the user the value of road use through automatic tolls. Congestion pricing allows higher tolls during times of higher demand to encourage mode-switching and flatten out the demand peak.
  • Charge market rates for all employee, consumer or residential parking. Delink the rent or purchase of residential or commercial parking from the rental or purchase of housing or commercial space.


Bay Area Air Quality Management District, Final Bay Area ‘97 Clean Air Plan, San Francisco, Dec. 1997.

Stacy Davis, Transportation Energy Data Book 17, U.S. Department of Energy, ORNL-6919, 1997.

Robert Dunphy and Kimberly Fisher. "Transportation, Congestion, and Density: New Insights," Transportation Research Record No. 1552, Washington DC: Transportation Research Board, November 1996, pp89-96.

Environmental Protection Agency, Transportation Partners 1997 Annual Report, 1998.

John Holtzclaw, Robert Clear, Hank Dittmar, David Goldstein and Peter Haas, "Location Efficiency: Neighborhood and Socio-Economic Characteristics Determine Auto Ownership and Driving: Studies in Chicago, Los Angeles and San Francisco", manuscript submitted for journal publication.

Todd Litman, Transportation Cost Analysis; Techniques, Estimates and Implications, Victoria Transport Policy Institute, 1250 Rudlin Street, Victoria, BC, V8V 3R7, Canada, 1998-1.

Todd Litman, Socially Optimal Transport Pricing and Markets; Victoria Transport Policy Institute, 1250 Rudlin Street, Victoria, BC, V8V 3R7, Canada, 1998-2.

Peter Miller and John Moffet, The Price of Mobility; Natural Resources Defense Council, 71 Stevenson Pl #1825, San Francisco CA 94105, 415-777-0220; Oct 93

Peter Newman and Jeffrey Kenworthy, Cities and Automobile Dependence: An International Sourcebook, Gower Publishing, 1989.

Organization for Economic Co-operation and Development, Choosing an Alternative Transportation Fuel: Air Pollution and Greenhouse Gas Impacts, 1993.

The President’s Council on Sustainable Development, Energy and Transportation, Task Force Report, 1996, U.S. G.P.O.: 1996-404-680:20028.

Donald Shoup, "Evaluating the Effects of Cashing Out Employer-Paid Parking: Eight Case Studies," School of Public Policy and Social Research, University of California, Los Angeles, 1997.

Wolfgang Zuckermann, End of the Road, Chelsea Green, 1991.

Table 1. Subsidies to Motor Vehicle Use in America

$/gal gas,diesel Annual Tot ($bil)

Ketcham & Komanoff 5.53 730

Litman 4.99 659

MacKenzie, Dower & Chen 3.03 400

Miller & Moffet 2.86 - 5.00 378 - 660

Office of Technology Assessment 3.39 - 6.81 447 - 899

OTA - incl non-monetary personal costs 11.17 - 16.11 1,475 - 2,127

(primarily own accid. & travel time)

Delucchi 3.13 - 7.55 413 - 997


Brian Ketcham & Charles Komanoff; Win-Win Transportation: A No-Losers Approach To Financing Transport in New York City and the Region; KEA, 270 Lafayette #400, New York 10012, 212-334-9767; July 92

Todd Litman, Transportation Cost Analysis; Techniques, Estimates and Implications, Victoria Transport Policy Institute, 1250 Rudlin Street, Victoria, BC, V8V 3R7, Canada, 1998.

James MacKenzie, Roger Dower & Donald Chen, The Going Rate: What It Really Costs To Drive; World Resources Institute, 1709 New York Ave NW, Washington DC 20006; June 92

Peter Miller & John Moffet, The Price of Mobility; Natural Resources Defense Council, 71 Stevenson Pl #1825, San Francisco CA 94105, 415-777-0220; Oct 93

Office of Technology Assessment, Saving Energy in U.S. Transportation; U.S. Congress, OTA-ETI-589, 1994

Mark Delucchi (Inst. of Transportation Studies, UC Davis, CA 95616), "Total Cost of Motor-Vehicle Use," Access, Spring 1996.


20 mpg average fuel consumption

132 109 gal/yr U.S. gasoline & diesel consumption - all road vehicles [106 109 gal/yr - autos & lt. tr.] S. Davis & S. Strang, Transportation Energy Data Book 13, ORNL-6743, 1993, Table 2.7

189 106 cars, trucks & buses in U.S. Davis & Strang

Sources of Subsidies

  • Police, fire, ambulance; road construction & maintenance; other local gov't
  • Property taxes lost from land cleared for freeways
  • Parking
  • Air, water, land pollution
  • Noise, vibration damage to structures
  • Global warming
  • Petroleum supply line policing, security, petroleum production subsidies
  • Trade deficit, infrastructure deficit
  • Sprawl, loss of transportation options
  • Uncompensated auto accidents
  • Congestion

-- John Holtzclaw

Up to Top | Printer-friendly version of this page