Stimpson and Wilson Respond

We agree that adjusting the fatality rates by size of each racial/ethnic population would provide a slightly more meaningful inference. However, population is not an ideal proxy for risk exposure, as Drs. Griswold and Grembek allude to in their letter.¹ The optimal method would be to calculate fatality rates based on the degree of risk exposure actually faced across the different groups in Table 1 of our article because, for example, the racial/ethnic distribution of miles traveled by pedestrians and cyclists—and their respective miles traveled—may differ significantly from the racial/ethnic population distribution.² Therefore, one would need to identify, for example, the population of Hispanic bicycle riders or, preferably, the number of miles traveled among Hispanic bicycle riders. Unfortunately, these data are not available in the database used for this study. That is why our discussion of Table 1 and use of the word “disproportionate” focused on the percentage distribution of victims across demographic and other characteristics rather than the rates.²

Distracted driving is a traffic safety threat that cuts across all groups, and one study alone is insufficient to understand this issue. We encourage more peer-reviewed research in this field, and more funding for this type of research, to accurately gauge the degree of risk of injury and death faced by specific groups on public roadways.