A slow and quiet transformation appears to have begun in the U.S. around the daily commute. According to recent publications, both in scientific journals and the mainstream media, commuters have begun to see a gap between the range of transportation options available to them and their underlying preferences.

What Commuters Want

• More transportation options – The Department of Transportation’s Bureau of Transportation Statistics recently released the results of a 2009 survey that asked 1,000 households to rank the importance of certain transportation infrastructures. Major roads/highways came in at first place (>90%). However, over 70% of respondents also supported sidewalks, local transit, and pedestrian friendly livability characteristics. While airport access and adequate parking also ranked highly (>80%), this survey may point to a trend away from a desire for an automobile-centered lifestyle.

• A shorter commute – 78% of respondents to the National Association of Realtors’ 2011 Community Preference Survey indicated that they would prioritize living within a thirty minute commute to work. And, 59% would trade a smaller house and lot if it reduced their commute time.

• A mixed-use, pedestrian-friendly neighborhood – The Community Preference Survey also found that 66% of respondents would prioritize living in an area within easy walking distance of amenities such as grocery stores, pharmacies, restaurants, and hospitals.

Cars: Asset or Inconvenience?

Given the preferences listed above, the question arises, is the single-occupancy vehicle becoming outmoded?

• Decline in car use – A recent article by Anita Elash in The Globe and Mail points to a trend of reduced car use in all industrialized countries (including the U.S., where, after decades of increasing vehicle miles traveled each year, car usage per capita has dropped to 1998 levels). She writes, “the shift is so gradual and widespread that it's clearly not a product of any ‘war on the car’ or other ideological campaign. Rather, it's a byproduct of a stage of development that cities were probably destined to reach ever since the dawn of the automobile age: Finding themselves caught in an uncomfortable tangle of urban sprawl, population growth and plain individual inconvenience, people, one by one, are just quietly opting out.”

• The “peak car” generation – This term, cited in publications such as Scientific American and The Independent, points to a demographic shift in industrialized countries. It appears that younger generations may not share their parents’ and grandparents’ fascination with cars. Other articles such as Krissy Clark’s post “Blame My Driving Habits on that Parking Spot” on the Climate Watch blog speak of the balance shifting away from the flexibility afforded by car use and towards the cost and inconvenience of finding parking spots once you reach your destination.

What Does This Mean for Our Health?

Pros

The benefits of alternative (or active) transportation have been extensively studied. In particular, the increase in levels of physical activity resulting from taking the bus, walking, or riding a bike rather than driving can have a myriad of beneficial health effects.

• Obesity – Engaging in regular physical activity can reduce obesity. Walking to and from the bus or subway as part of the work commute often meets the recommendations of the 2008 Physical Activity Guidelines for Americans: 2.5 hours of moderate physical activity per week. The Active Living Research Literature Database (funded by the Robert Wood Johnson Foundation) offers an extensive review of the literature linking physical activity and obesity.

• Diabetes & Heart Disease – The onset of Type 2 Diabetes and heart disease can be slowed or prevented through a combination of physical exercise and nutrition (Blair & Morris, 2009).

• Mental Health – Using alternative forms of transportation enhances mental health both by removing the stress of driving on congested roads and by increasing physical activity (Taylor & Dorn, 2006). It also can provide mental health benefits by increasing commuters’ daily dose of green spaces (Sick Nielsen & Bruun Hansen, 2007).

Cons

In spite of its many health benefits, alternative transportation can also lead to negative health outcomes, if the built environment is not designed to accommodate it.

• Injury – According to the U.S. Centers for Disease Control and Prevention, injury (including pedestrian-motor vehicle collisions) is the leading cause of death in the U.S. among persons 1-44 years. However, in many cases, these injuries are preventable through modifications to the built environment (Retting et al., 2003).

• Respiratory & Cardiovascular Disease – The six criteria air pollutants regulated by the U.S. EPA (carbon monoxide, sulfur oxides, nitrogen oxides, ozone, lead, and particulate matter) can cause both short-term, acute respiratory and/or cardiovascular effects and exacerbate chronic diseases, such as asthma. While the long-term effect of encouraging alternative transportation is likely to be a reduction in street-level air pollution (Frank et al., 2006), the short-term effect may be increased exposure (Carlisle and Sharp, 2001), because physical activity can lead to faster, deeper breathing and inhalation through the mouth rather than the nose, which filters out many pollutants before they can reach the lungs.

Removing Barriers

With the trend moving away from the car and towards a more varied approach to transportation choices, it is becoming clear that, in many communities in the U.S., the built environment actively prevents widespread use of alternative transportation. These obstacles may take the form of physical barriers (i.e., the absence of bike trails and sidewalks) or mental barriers (i.e., the assumption that driving equates to independence). In an extreme example, the MoveArkansas blog describes a crosswalk at a popular intersection in Little Rock, Arkansas, that actually bans pedestrians from 6am to 6pm, Monday through Friday.

In spite of the these challenges, a number of innovative programs across the country are trying out new ways to modify the built environment that both remove barriers to alternative transportation and reduce potential negative health effects:

• Offer seniors an alternative to the car – Elderly populations represent the highest fatality rates in the U.S. for pedestrian-motor vehicle collisions (Beck, Dellinger, & O'Neil, 2007). Recognizing the severity of this problem, programs such as the U.S. EPA’s National Agenda for the Environment and the Aging have begun to promote community development plans that integrate the elderly into smart growth developments through applicable housing options and opportunities for civic engagement.

• Safety through numbers – New York City has taken the position that increasing the number of cyclists on the road is the most effective way to protect them from collisions with motor vehicles. As a result, when it launches its bike share program in 2012, the City will not require adult bike share riders to wear helmets, which are seen as a deterrent to ridership.

• Wildlife crossings – High injury rates among another vulnerable population, wildlife, have led to the development of the emerging field of road ecology, which integrates wildlife crossings into transportation infrastructure design.

• Improve localized air quality – Akbari et al. (2001) found that policies aimed at mitigating the urban heat island effect through light-colored roofs, streets, and sidewalks, as well as increasing vegetation through tree planting and vegetative roofs could reduce the number of ozone action days, in addition to saving $10B per year nationwide in reduced air conditioning use.

As seen above, projects aimed at removing barriers to alternative transportation can benefit from developing a deep understanding of their environmental and health context. Health Impact Assessments offer recommendations that allow design solutions both to be tailored to the specific needs of the population they serve and to avoid unintentional exposure to harm. Visit our blog post, “Health Impact Assessments: A Design Tool?,” for additional information about the role Health Impact Assessments can play in the design process.

References

Active living research literature database. Robert Wood Johnson Foundation. (link)

Akbari, H, Pomerantz, M, Taha, H. (2001). Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas. Solar Energy, 70(3), 295-310. (link)

Beck, Laurie, Dellinger, Ann, O’Neil, Mary. (2007). Motor vehicle crash injury rates by mode of travel, United States: Using exposure-based methods to quantify differences. American Journal of Epidemiology, 166(2), 212-218. (link)

Belden Russonello & Stewart. (2011, March). The 2011 community preference survey: What Americans are looking for when deciding where to live. (link)

Blair, Steven, Morris, Jeremy. Healthy hearts—and the universal benefits of being physically active: Physical activity and health. (2009). Annals of Epidemiology, 19(4), 253-256. (link)

Carlisle, A. J., Sharp, N. C. C. Exercise and outdoor ambient air pollution. (2001). British Journal of Sports Medicine, 35, 214-222. (link)

Clark, Krissy. Blame my driving habits on that parking spot. (2011, September 29). Climate Watch. (link)

Elash, Anita. Are we reaching “peak car”? (2011, October 22). The Globe and Mail. (link)

Farrell, Sean Patrick. A gentle push for bikers, not a shove. (2011, October 14). The New York Times. (link)

Frank, Lawrence, Sallis, James, Conway, Terry, Chapman, James, Saelens, Brian, Bachman, William. Many pathways from land use to health: Associations between neighborhood walkability and active transportation, body mass index, and air quality. (2006). Journal of the American Planning Association, 72(1), 75-87. (link)

Guarino, Jenny, Pheny Weidman. Public perceptions on transportation characteristics of livable communities: The 2009 omnibus household survey. (2011, July). U.S. Department of Transportation Research and Innovative Technology Administration Special Report. (link)

McKuin, Tim. A city for cars or for people? (2011, October 4). MoveArkansas. (link)

Sick Nielsen, Thomas, Bruun Hansen, Karsten. Do green areas affect health? Results from a Danish survey on the use of green areas and health indicators. (2007). Health & Place, 13(4), 839-850. (link)

Taylor, Adrian, Dorn, Lisa. Stress, fatigue, health, and risk of road traffic accidents among professional drivers: The contribution of physical inactivity. (2006). Annual Reviews of Public Health 2006, 27, 2.1-2.21. (link)

Tepper, Laura. Road ecology: Wildlife habitat and highway design. (2011, September 22). Design Observer. (link)

Retting, Richard, Ferguson, Susan, McCartt, Anne. A review of evidence-based traffic engineering measures designed to reduce pedestrian-motor vehicle crashes. (2003). American Journal of Public Health, 93(9), 1456-1463. (link)

U.S. Centers for Disease Control and Prevention. The burden of injury and violence: A pressing public health concern. (link)

U.S. Department of Health & Human Services. 2008 Physical activity guidelines for Americans. (link)

U.S. Environmental Protection Agency. Effects of air pollutants: Health effects. (link)

U.S. Environmental Protection Agency. National agenda for the environment and the aging. (link)

Voorhees, Josh. Has the U.S. reached peak vehicles? (2012, January 6). Scientific American. (link)

Witchalls, Clint. Is this the end of the car? (2011, May 20). The Independent. (link)

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