Analysis of statewide pedestrian fatality and injury data indicates that the most dangerous places for pedestrians tend to be newer, sprawling communities in southern California, the Central Valley and Silicon Valley. These are communities where restrictive local zoning codes often mandate the separation of shops, schools, businesses and houses, and the resulting distances between destinations have made walking, bicycling and even mass transit inconvenient and inefficient. Dropping off dry cleaning, going to work, stopping by day care, and picking up groceries now often requires four separate driving trips. Ten or 20 years ago at least two or three of these trips could easily have been made on foot. These multiple errands, what transportation experts refer to as "trip-chaining," are often done during morning and evening rush hour on the way to and from work, putting an additional strain on already congested roadways.

The recent rise of the so-called "soccer mom" is another testament to the loss of childhood mobility by foot or on bike that just a generation ago was taken for granted. The loss of mobility for children has significant societal impacts that are only just beginning to be realized. It is exactly these types of physical environments, often characterized as "sprawl," that appear to be some of the most dangerous places for pedestrians. Indeed, a 1993 study found that suburban children were at greater risk from traffic than urban children were at risk from gun violence.(11)

The best estimates for the relative danger of pedestrian environments are those that take into account total pedestrian fatalities and injuries, population, and the best data available for overall exposure, or the amount walked. Assessments of relative dangers for pedestrians should include some measure of the level of pedestrian activity in an area. If, for example, in a given year a county only recorded two pedestrian fatalities at a specific intersection, it would make a great deal of difference whether ten people had crossed the intersection or ten thousand people had crossed. This is one disadvantage with calculating pedestrian fatality and injury rates by population alone—it fails to take into account relative risks and overall exposure. San Francisco County—one of the densest counties in California with the highest level of pedestrian activity—has one of the highest pedestrian injury rates based on population alone. Yet when adjusted for the amount of walking and the rough number of pedestrians, i.e. "exposure," San Francisco drops in its relative ranking for overall danger for pedestrians while more suburban counties like Orange, Santa Clara and Sacramento will appear higher than if ranked based solely on population (see Methodology section for more details).

Table 1 ranks the most populous 35 counties in California according to a "pedestrian danger index." The index incorporates the most recent data available from the Statewide Integrated Traffic Records System managed by the Department of California Highway Patrol, recently revised population figures from the California Department of Finance, and U.S. census journey to work data, the best available surrogate for levels of pedestrian activity. The incident (fatality plus injury) rates per population are then adjusted for overall exposure, and a relative index is calculated assigning a 100 score for the most dangerous. A 1997 ranking in the second column of Table 1 also allows comparison between two years of data.

Areas characterized by low density development, those that also consistently rank high on the pedestrian danger index, are becoming increasingly the norm in cities, suburbs and on the outskirts of towns all across the state. Unfortunately, given the prevalence of current road and subdivision design practices and the many fiscal and regulatory incentives that encourage sprawl, the future may hold more of the same. Unless things change, getting around on foot—due in part to the increasing trend towards these types of physical environments—could become even more impractical and dangerous. For children and the elderly, the trend towards low-density development—characterized by the proliferation of housing-only subdivisions, big box retail, and the ubiquitous "highway strip" —will continue to make walking or bicycling inconvenient and unsafe, robbing thousands of Californians of much needed independence.