How Risky is It? An Assessment of the Relative Risk of Engaging in Potentially Unsafe Driving Behaviors

Abstract

This report presents the results of a two-phased project funded by the AAA Foundation for Traffic Safety. The data used for the analyses in this report were collected during the 100-Car Naturalistic Driving Study, or the 100-Car Study, (Dingus, Klauer, Neale, Petersen, Lee, Sudweeks et al. 2006), conducted by the Virginia Tech Transportation Institute (VTTI), under sponsorship from the National Highway Traffic Safety Administration (NHTSA), Virginia Department of Transportation (VDOT), and Virginia Tech. The primary aim of the current study was to increase the understanding of the relationship between potentially unsafe driving behaviors as well as crashes, near-crashes, and incidents. The results indicate that four driving states/behaviors are associated with an increased risk of being involved in a crash or near-crash. First, driving at inappropriate speeds was associated with nearly tripling the odds of being involved in a crash or near-crash (OR = 2.9, 95% CI = 1.7 – 4.8) relative to driving at appropriate speeds. Second, driving while drowsy was associated with a similar increase in the odds of being involved in a crash or near-crash, relative to driving while not drowsy (OR = 2.9, 95% CI = 2.0 – 4.3). Third, when a driver’s eyes were off the forward roadway for greater than 2 seconds, the odds of a crash or near-crash occurring were nearly double those when the driver was paying attention to the forward roadway (OR = 1.9, 95% CI = 1.4 – 2.5). Finally, the odds of a crash or near-crash more than doubled when a driver was exhibiting aggressive driving behaviors (OR = 2.1, 95% CI = 1.3 – 3.4).