Transportation and public health interact in several ways, such as in the areas of public safety and exposure of the public to air pollution. In this regard, there has been improvement in some critical indicators of transportation’s health impacts over the last several decades.

As is discussed in chapter 6, transportation fatalities and injuries have declined in recent decades, yet every day, on average, about 95 people die and 6,400 people are injured in transportation accidents—primarily on the highway. Air pollution from transportation also is an indicator of health effects, as is discussed in chapter 7. Here, too, there has been a reduction in transportation emissions over the last few decades, resulting in benefits to public health.

Perhaps the most dramatic change has been the virtual elimination of lead from gasoline. This phase out brought major public health benefits, particularly for children and populations living near major highways who were no longer exposed to unhealthy levels of lead from gasoline emitted into the air. Lead when inhaled or ingested from soil was shown to produce elevated lead levels in the blood, with multiple health effects such as lowering IQs for exposed children, and cardiovascular problems for adults [WORLD BANK 1998].

But air quality health impacts from transportation emissions from other air pollutants remain a concern. According to the US EPA, living, working or attending school near major roads has been associated with greater incidence or severity of such health effects as asthma, cardiovascular disease, reduced lung function, childhood leukemia, and premature death. Besides air pollution, noise exposure may also play a role in roadway- related health problems [USEPA].

The mode of transportation people use also impacts health. Americans increasingly have an obesity problem, in part because of diet and sedentary lifestyles, and in many cases lack of exercise. During the last half century, the time people spend each day walking and bicycling to workplaces or other places has declined, while the time spent sitting in vehicles has increased [AJPH 2011]. Census Bureau reports show that in 1960, 10.3 percent of people walked to work, compared to 2.8 percent in 2013. People also are less likely today than in the 1960s to use public transit, which generally involves walking to and from a bus stop or transit station.

The NHTS found that people averaged 1 hour a day in their vehicles as a passenger or a driver in 2009. This was less time than in 2001 but more time than in 1990 [USDOT FHWA 2011]. The amount of time spent in a vehicle varied by age group, from somewhat more than 40 minutes a day for children under the age of 18 (those less than 5 were not tallied) to over 70 minutes per day for those between 35 and 54 years of age. The 2009 NHTS survey found that walking accounted for 10 percent of daily trips—an increase from 8.6 percent in 2001.

The complex interactions between transportation and public health are increasingly recognized as an aspect of transportation planning. Several states and communities are explicitly addressing these connections in their statewide transportation plans. At the federal level, several USDOT agencies participate in a health in transportation working group. The working group also participates with other groups, such as the U.S. Department of Health and Human Services’ Centers for Disease Control and the Transportation Research Board in sponsoring workshops and other activities designed to bring health issues to the fore in transportation planning.