Research has shown that some of the most successfully engineered safety interventions are often unnoticed factors in the environment. Everyday examples are roadway modifications that help drivers stay on the road rather than going off the road at curves or other hazardous locations (TRB, 1990), guard railings on upper-level terraces, and window guards to prevent childhood falls (Spiegel and Lindaman, 1977; Barlow et al., 1983). Through research, safety engineers and injury specialists have been able to modify building codes and change engineering designs to build in these safety features.
In recent years, increasing attention has been paid to preventing assaultive injuries through changes in environmental design. Examples of environmental changes include improved lighting in parking lots, the addition of police call-boxes, installing plexiglass shields for lone employees who need to handle cash transactions especially at night, and locating automatic teller machines in well-lit, high-traffic areas. Creative environmental interventions include efforts to reduce the incentives for committing robbery by using exact fare systems on public transport (Chaiken et al., 1974).
Any planned intervention designed to reduce injuries occurs in the context of broad economic and social forces, such as employment rates, wealth distribution, social norms about health and safety, and population demography, that also fundamentally shape injury rates. Economic conditions, social practices, and cultural understandings constitute the context for of all these other factors and the prospect of altering them. Death rates are high in low-income areas for most types of unintentional injuries and for homicide; however, for suicide, there is little relationship between injury death rate and per capita income (Baker et al., 1992). Racial disparities in childhood unintentional injury rates are associated more with living in impoverished environments that with ethnicity (Singh and Yu, 1996; SAFE KIDS, 1998).
An example of the impact of the socioeconomic environment is seen in the increases in the rate of highway fatalities during economic upturns and the decreases during recessions (Graham, 1993). People tend to drive more during boom times, and the fatality rate per mile also increases (relative to long-term trends) as the economy expands, probably because more miles are driven by more high-risk drivers such as teenagers and people who have been drinking. This example illustrates two points. First, researchers studying the effects of planned injury prevention interventions on injury rates must always be alert to the effects of these background socioeconomic trends and conditions. Second, some types of public policies can be utilized explicitly as levers of injury prevention, even though they are not ordinarily seen from this perspective. A good