If you’re an American and commuted to work today, the odds are that you drove there alone. According to a 2011 Census Bureau report, in 2009 more than three-quarters of all commuters were in single-occupancy vehicles — that’s 105 million cars, one by one down the highway. While the ongoing financial crisis has pushed more commuters to save money by carpooling and using public transit, the vast majority continue to drive alone. In 2009 the average travel time was just over 25 minutes, meaning that nearly an hour of every workday was spent in a car.
The same year, 5% of commuters in the United States used public transportation, 2.9% walked to work and 0.6% rode bikes. While these figures may seem minor in the overall picture, in dense cities with the appropriate infrastructure, non-automotive modes can contribute significantly to mobility: 30% of residents in the New York, Northern New Jersey, Long Island metropolitan area get to work by mass transit, while 15% of those in the San Francisco, Oakland, and Fremont area do. Nearly 10% of Corvallis, Ore., residents bike to work, while 15% of those in Ithaca, N.Y., choose to walk.
Of course, transit infrastructure is frequently not in place to help people get to their place of employment. A 2011 Brookings Institution report found that only 30% of jobs in metropolitan areas can be reached by transit within 90 minutes. Access varies significantly, from 60% in Honolulu to 7% in Palm Bay, Florida; Washington and New York average 37%. The report also highlighted some inequalities: About 33% of high-skill jobs can be accessed by transit within 90 minutes, compared to 25% of low- and middle-skill jobs.
According to a report by the Center for Housing Policy, U.S. working families spend 29% of their income on transportation — more than $9,800 on average. Those living in dense cities with extensive mass transit systems tended to have lower transportation costs (New Yorkers paid $7,880, nearly 20% less than the average) while those in cities that sprawl have higher costs (Atlantans spent $10,890, 11% more than the average). More driving also increases a city’s per-capita carbon footprint: In New York, residents are responsible for 1.9 metric tons of carbon per year; in Los Angeles, the figure is 3.68 — nearly double.
One factor influencing individuals’ choices is free parking at work, and research has shown that the option of “cashing out” can significantly increase rates of carpooling and other alternate transportation modes. Other subsidies for driving are hidden in the tax code: Up until this year, those who commuted by car could deduct $240 for parking costs; mass transit users only got $125. That imbalance was rectified in the “fiscal cliff” bill approved New Year’s Day 2013.
Below is a selection of recent research on issues related to the major commuting modes, including cars, transit, bicycles and walking.
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“Commuting in the United States: 2009”
United States Census Bureau, American Community Survey Reports, September 2011.
Summary: “Commuting in the United States is dominated by private automobile travel, as is evidenced by the large proportion (86.1 percent) of workers 16 years and over who commuted by car, truck, or van in 2009. About three-quarters of workers drove to work alone in that year. The dominance of the automobile at the national level should not obscure the considerable variation in modal usage across geographic areas…. Several smaller metropolitan areas have high proportions of workers who commute by walking or bicycle, and transit commuters are concentrated within a small number of large metropolitan areas. Differences in average travel times also vary geographically. The metro areas with the shortest travel times tend to have smaller populations, while the longest commutes are associated with the nation’s largest metro areas.”
“Not Driving Alone? American Commuting in the Twenty-first Century”
DeLoach, Stephen B.; Tiemann, Thomas K. Transportation, May 2012, Vol. 29, Issue 3. doi: 10.1007/s11116-011-9374-5.
Abstract: “This paper investigates recent commuting trends by American workers. Unlike most studies of commuting that rely on data from the American Community Survey this study utilizes the American Time Use Survey to detail the complex commuting patterns of modern-day workers. Changes in the price of gasoline in recent years suggest that the incidence of ‘driving alone’ should be on the decline. Indeed, results show that the sensitivity of modal commuting with respect to changes in gasoline prices appears to be relatively large. We estimate the gasoline-price elasticity of driving alone to be 0.057 and the gasoline-price elasticity of carpooling to be 0.502. Additional factors also affect commuting, including socio-economic characteristics and social desires. However, it is changes in gasoline prices that appear to account for nearly all of the recent variation in the mode chosen for commuting.”
“Driving to Opportunity: Local Wages, Commuting and Sub-Metropolitan Quality of Life”Albouy, David; Lue, Bert. University of Michigan, National Bureau of Economic Research, August 2011.
Conclusion: “We find as much variation in quality-of-life within metropolitan areas as we do across them. In particular, the highest amenity areas are generally found in denser suburbs, while low-density rural areas are the least amenable: these conclusions are only clear when commuting and residential selection are controlled for. Furthermore, the geographic detail of the data — the best available nationwide for public use — makes it easier to identify how much households value location-specific amenities, providing cross-sectional evidence, both within and across metropolitan areas, that households put great value on safety, schools, and leisure amenities, as well as mild climates and scenic geography.”
“Commuting by Public Transit and Physical Activity: Where You Live, Where You Work and How You Get There”
Lachapelle, U.; Frank, L.; Saelens, B.E.; Sallis, J.F.; Conway, T.L. Journal of Physical Activity and Health, 2011.
Results: “Regardless of neighborhood walkability, those commuting by transit accumulated more [moderate-intensity physical activity] MPA (approximately 5 to 10 minutes) and walked more to services and destinations near home and near the workplace than transit nonusers. Enjoyment of physical activity was not associated with more transit commute, nor did it confound the relationships between MPA and commuting. Conclusion: Investments in infrastructure and service to promote commuting by transit could contribute to increased physical activity and improved health.”
“Determinants of Bicycle Commuting in the Washington, D.C., Region: The Role of Bicycle Parking, Cyclist Showers and Free Car Parking at Work”
Buehler, Ralph. Transportation Research Part D: Transport and Environment, October 2012, Vol. 17, Issue 7. doi: 10.1016/j.trd.2012.06.003.
Abstract: “This article examines the role of bicycle parking, cyclist showers, free car parking and transit benefits as determinants of cycling to work. The analysis is based on commute data of workers in the Washington, D.C., area. Results … indicate that bicycle parking and cyclist showers are related to higher levels of bicycle commuting — even when controlling for other explanatory variables. The odds for cycling to work are greater for employees with access to both cyclist showers and bike parking at work compared to those with just bike parking, but no showers at work. Free car parking at work is associated with 70% smaller odds for bike commuting. Employer-provided transit commuter benefits appear to be unrelated to bike commuting.”
“The Role of Attitudes Toward Characteristics of Bicycle Commuting on the Choice to Cycle to Work Over Various Distances”
Heinen, Eva; Maat, Kees; van Wee, Bert. Transportation Research Part D: Transport and Environment, March 2011, Vol. 16, Issue 2. doi: 10.1016/j.trd.2010.08.010.
Abstract: “Factor analysis reveals three underlying attitudinal factors toward cycling to work: awareness, direct trip-based benefits and safety. The decision to cycle is influenced by the factor ‘direct trip-based benefit’ at all distances, whereas the ‘awareness’ is influential only over long distances. The decision to cycle every day is again affected by the ‘direct benefit’ factor. The factors ‘safety’ and ‘awareness’ are important over shorter distances. Having a cycling habit increases the likelihood of cycling and a higher frequency of cycling. The perceived opinion of others only affects the mode choice over short distances suggesting … mode choice on longer commutes is based on one’s own attitudes. These findings indicate that attitudes and other psychological factors have a relatively strong impact on the choice to commute by bicycle.”
“Do the Health Benefits of Cycling Outweigh the Risks?”
Hartog, Jeroen Johan de; et al. Environmental Health Perspectives, August 2010, 118(8). doi: 10.1289/ehp.0901747.
Abstract: “We quantified the impact on all-cause mortality when 500,000 people would make a transition from car to bicycle for short trips on a daily basis in the Netherlands. We have expressed mortality impacts in life-years gained or lost, using life table calculations. For individuals who shift from car to bicycle, we estimated that beneficial effects of increased physical activity are substantially larger (3-14 months gained) than the potential mortality effect of increased inhaled air pollution doses (0.8-40 days lost) and the increase in traffic accidents (5-9 days lost). Societal benefits are even larger because of a modest reduction in air pollution and greenhouse gas emissions and traffic accidents.”
“A Heavy Load: The Combined Housing and Transportation Burdens of Working Families”
Lipman, Barbara J.; et al. Center for Housing Policy, October 2006.
Introduction: “On average, the study found that working families in the 28 metropolitan areas spend about 57% of their incomes on the combined costs of housing and transportation, with roughly 28% of income going for housing and 29% going for transportation. While the share of income devoted to housing or transportation varies from area to area, the combined costs of the two expenses are surprisingly constant. In areas where families spend more on housing, they tend to spend less on transportation, and vice-versa.”
“It’s Driving Her Mad”: Gender Differences in the Effects of Commuting on Psychological Health”
Roberts, Jennifer; Hodgson, Robert; Dolan, Paul. Journal of Health Economics, September 2011. doi: 10.1016/j.jhealeco.2011.07.006.
Abstract: “Our results show that, even after these variables are considered, commuting has an important detrimental effect on the psychological health of women, but not men, and this result is robust to numerous different specifications. We explore explanations for this gender difference and can find no evidence that it is due to women’s shorter working hours or weaker occupational position. Rather, women’s greater sensitivity to commuting time seems to be a result of their larger responsibility for day-to-day household tasks, including childcare and housework.”
Keywords: cars, mass transit, driving, bicycling, research roundup