other road users, preventing other drivers from passing, driving at speeds “far in excess of the norm,” running stop signs or red lights, and several others.
Somewhat similarly, in a report published by the Transportation Research Board, Neuman et al. (2003) define aggressive driving as, “operating a motor vehicle in a selfish, pushy, or impatient manner, often unsafely, that directly affects other drivers.” (pg. I-1) They further define aggressive driving as a “contextual violation,” dependent upon the driver’s psychological state and environmental factors such as traffic conditions that are present when a behavior is performed. They also note that there is wide variation in estimates of the extent of aggressive driving.
A report published by the National Highway Traffic Safety Administration (NHTSA) states that aggressive driving “is generally understood to mean driving actions that markedly exceed the norms of safe driving behavior and that directly affect other road users by placing them in unnecessary danger.” (2009, pg. 3-1). This report states that “immature” and “selfish” driving behavior may be typical of a small proportion of drivers, but that the vast majority may respond to specific provocation, for example due to frustration with traffic conditions, by driving in an aggressive manner.
In an online report by NHTSA for the law enforcement community, NHTSA (n.d.) defines aggressive driving as “when individuals commit a combination of moving traffic offenses so as to endanger other persons or property.” Having been written for the law enforcement community, this definition refers to “offenses” rather than simply “behaviors,” however, an important element of this definition is the concept of combinations of offenses (or behaviors). Arguably, combinations of behaviors—each of which may or may not necessarily be indicative of aggressive driving on its own—may be more likely to be indicative of aggressive driving than individual behaviors in isolation. For example, as shown subsequently, 30.7 percent of all fatal crashes from 2003 to 2007 involved a speeding driver, and 11.4 percent involved a driver who reportedly failed to yield the right of way. Either of these behaviors could have been committed purposely—in an aggressive manner—or unintentionally as the result of an error, but when a driver performs both of these behaviors at the same time, it is arguably more likely that the driver did so on purpose rather than accidentally.
We contend that any unsafe driving behavior, performed deliberately and with ill intention or disregard for safety, can constitute aggressive driving. However, as noted earlier, existing sources of data on motor vehicle crashes do not include information about the motivations or intentions of drivers, therefore, attempts to estimate the prevalence of aggressive driving using motor vehicle crash data must rely on information about the driver’s actions.
© 2009, AAA Foundation for Traffic Safety