emotional state unrelated to aggressive driving, such as depression. Both of these codes are used extremely rarely in FARS—Road Rage / Aggressive Driving was coded in 0.2 percent of all fatal crashes from 2004 to 2007, and Emotional was coded in 0.3 percent of all fatal crashes. Given the disparate types of scenarios that either of these codes may be used to indicate, neither was analyzed any further nor included in the statistics cited in this study.
We attempted to analyze trends over time in the contribution of these potentially-aggressive driver-related factors to fatal crashes; however, exploratory data analysis revealed implausibly large yearly fluctuations in the percentage of fatal crashes in which these factors were coded in some states suggested that changes in police reporting procedures or data coding procedures would likely render trend analysis invalid. Most saliently, it was evident that the reporting of some of the driver-related factors analyzed herein decreased markedly in recent years, much more sharply than could be attributable to improvements in driver behavior, and most likely attributable to changes in the forms used by police to record information about crashes.
Similarly, a comparative analysis of the contribution of factors suggestive of aggressive driving in different states was not performed, as it was suspected that state-to-state variation in reporting or coding procedures would bias comparisons across states. These issues also suggest that although the estimates of the role of these potentially-aggressive actions are the best estimates that can be produced from available data, the true frequencies with which these actions are involved in fatal crashes may be somewhat lower or higher than those reported here.
Irrespective of whether or not the potentially-aggressive actions cited in this study were committed intentionally or accidentally, the fact that 56 percent of fatal crashes are associated with speeding, failure to yield the right of way, recklessness, carelessness, and other such behaviors is very disturbing. Each and every one of these behaviors is unacceptable, dangerous, and is inconsistent with the positive traffic safety culture the Foundation is seeking to promote.
The traffic safety community has not adopted a standard definition of aggressive driving. We contend that any unsafe driving behavior that is performed deliberately and with ill intention or disregard for safety constitutes aggressive driving. However, due to the limitations of the available data on motor vehicle crashes, it is not possible to ascertain a driver’s intentions or motivations, thus this research focused on observable driver behaviors that were reported in police investigations to estimate the contribution to fatal crashes of behaviors typically associated with aggressive driving.
© 2009, AAA Foundation for Traffic Safety