In December 1995, Cynthia Wiggins was hit by a dump truck while crossing several lanes of traffic in suburban Buffalo, New York; shortly afterward, she died from her injuries. The 17-year-old African-American woman had to cross the arterial road from her bus stop because the bus that took her from downtown to her job in the posh Walden Galleria mall was not allowed on mall property. It was later revealed that the local public transportation authority had for years tried, unsuccessfully, to get permission to stop in the mall's parking lot. In 1999, a lawsuit charging the mall's owners with racial discrimination was settled for $2.55 million (to benefit Ms Wiggins' son) without admission of liability.
Ms Wiggins' death is an especially dramatic example of the connections between transportation policy and social exclusion: specifically, support for a form of apartheid in the United States long after it was challenged in legislation and jurisprudence. In Los Angeles, The Bus Riders' Union has used a variety of tactics, including litigation under national civil rights legislation, to seek improvements in a transit service that mainly serves a darker-skinned, subaltern population unable to afford the costs of driving in a car-oriented metropolis. Although we are not (yet) familiar with similar extremes in Canada, an important and neglected 2009 report prepared for Human Resources and Social Development Canada on mobility and social exclusion in Hamilton, Toronto and Montréal concluded that "the evidence uncovered in terms of mobility and accessibility patterns is suggestive of social exclusionary processes that may prevent various vulnerable groups," specifically low income people, seniors and single parent households, "from accessing the places required for their daily needs." Since social exclusion functions as a social determinant of (ill) health, the role of transportation in social exclusion should automatically be of concern to the public health community.
There are more immediate reasons for concern. One involves the health consequences of transport-related (mainly automotive) air pollution, reviewed among many other places in a 2005 WHO-Europe report and in the same year by the Ontario College of Family Physicians. It is also likely that an inverse relation exists between income and exposure, although the relation is complicated both by the limitations of measuring exposure based on residential location (most people don't spend most of their time at home) and by the "particular social geography" of cities like Montréal. (I would be delighted if readers can identify useful literature reviews on this topic.)
A second issue is the relation between metropolitan form and injuries and deaths from road accidents, where data on the socioeconomic gradient are hard to find and primary data are often collected by law enforcement agencies, using categories that have limited relevance to population health. (Again, readers are invited to contribute sources to the conversation.) A 2003 article by Reid Ewing and colleagues developed a "sprawl index" for 448 metropolitan counties in the United States, matched this against "all-mode" traffic fatality statistics, and concluded that "sprawl is a significant risk factor for traffic fatalities, especially for pedestrians." In the ten counties with the most compact urban form, fatality rates averaged 5.6 per 100,000 population; in the ten counties with the least compact form – that is, the most sprawling ones – the average was 26.3 per 100,000 population. However, hazardous environments for pedestrians are common even in cities that are relatively compact by North American standards.
Hazardous environments for pedestrians are common, as shown in this picture taken from the University of Ottawa’s downtown campus.
A third reason for concern involves the relation among transport policy, the built environment, and overweight and obesity, which are now recognized as one of the most urgent public health challenges. The idea of obesogenic environments has gained widespread acceptance, and represents an essential challenge to the emphasis on 'lifestyles' or 'healthy choices' that characterizes many health promotion efforts. Isolating the specific contribution of transport policy is complicated by the fact that in the metropolitan environment, many things are going on at once. For example, neighbourhoods may be more conducive to physical activity ('walkable'), but may also have few full-service grocery stores but lots of convenience stores and fast-food outlets, or neighbourhoods where the built environment is conducive to walkability may also be those where crime is highest. However, some evidence shows a direct link between settlement patterns or transportation and obesity. For example, a 2004 study using a sprawl index – not the same one used by Ewing and colleagues – and self-reports of Body Mass Index (BMI) found that each 1-point increase in the sprawl index (on a scale of 100, values for large US metropolitan areas ranged from 6 to 100) was associated with a 0.5 percent increase in the risk of obesity, after individual-level variables like income, gender, age and education were controlled for. Almost by definition, urban sprawl implies a high reliance on automobiles for transportation, as shown in a classic graph produced by Jeffrey Kenworthy.
Source: P. Newman and J. Kenworthy, “‘Peak Car Use’: Understanding the Demise of Automobile Dependence,” World Transport Policy and Practice 17 (June 2011), reproduced with permission.
Finally, there is the need to shift transportation patterns in order to limit climate change, which itself is likely to have substantial adverse health impacts that will be inequitably distributed, falling first and hardest on people and regions that contributed least to the buildup of greenhouse gases. A 2009 article in The Lancet pointed out that transport emissions are rising faster than all other categories, and argued using scenarios for London and Delhi that there would be substantial health benefits from moving to "sustainable transport" including both lower-emission motor vehicles and more walking and cycling, quite independent of the effects on climate change. Elsewhere, a recent assessment of the effects of reducing automobile usage for short trips (1.6 km or less) in the Midwestern United States came to similar conclusions, and further projected several billion dollars a year in health care cost savings. As with other studies cited here these are only selections from a very large literature, but the pattern is clear.
So far as I know, the acronym HEST (for Healthy, Equitable and Sustainable Transportation) is my own invention. There is no shortage of useful information about how to begin, starting with a WHO evidence review mentioned in an earlier posting that identified transportation as an important area for action to reduce health inequity. Kenworthy has listed "ten key transport and planning decisions for sustainable city development," including de-emphasis of freeway and road; planning for employment and housing growth in the city centre and sub-centres; and – critically – a planning process that "is a visionary 'debate and decide' process, not a 'predict and provide,' computer-driven process." (A recent Toronto Star commentary on how the city's planning is now driven by the "pseudo-science" of traffic engineering made a similar point.) Ewing and colleagues have described the "five D's of development": density, diversity, design destination accessibility, and distance to transit. This source is one chapter in an excellent book called Making Healthy Places published by Island Press. World Streets, a web site specifically devoted to "equity-based transport," is another valuable and provocative resource.
Some Canadian organizations have taken up the challenge. I've already mentioned the work of the Ontario College of Family Physicians. In 2007, Toronto Public Health produced a report on air pollution, traffic and health that concluded: "Given there is a finite amount of public space in the city for all modes of transportation, there is a need to reassess how road space can be used more effectively to enable the shift to more sustainable transportation modes" like "walking, cycling and on-road public transit." (I don't think the city's current mayor has read it.) And Alberta Health Services has produced a well researched and hard-hitting fact sheet on urban sprawl and health. Doubtless much more is going on, and I hope readers will post appropriate news, citations and links.
Predictably, our colleagues in other countries have been less polite and more proactive. Margaret Douglas and colleagues in Britain's NHS (including the Director of Public Health for a primary care trust in Manchester) wonder whether cars are the new tobacco, pointing to the multiple negative effects on health and sustainability of auto-oriented transport systems and the influence of the "car lobby." Also from the UK, writing in the December, 2011 issue of Public Health Today Philip Insall calls for a 20 mph speed limit in residential areas, noting that some continental cities have already made this move and that it would eliminate up to 580 child deaths and serious injuries each year. (Lower speed limits are just one kind of traffic calming measure; many others involve design changes, as noted in an important review by the Canada's National Collaborating Centre for Healthy Public Policy just released last November.) And Andy Jones, writing about obesogenic environments, says: "Maybe we just need to force society to change. Excluding traffic from city centres, radically increasing parking charges, forcing employees to walk at least part of the way to work by removing workplace car parks" as well as taxing high-fat foods.
Forcing society to change can be difficult when we have things like elections, and that's as it should be. Canada's public health community could, however, be much more energetic in advocating for such changes, and providing leadership to ensure that their equity and health benefits are part of the public debate during and between elections.
* Unfortunately, as with previous postings some hyperlinks lead to sources that are not available on an open-access basis. I have tried to find open-access materials wherever possible.