Distracted Driving and Driver, Roadway, and Environmental Factors

Traffic Safety Administration, in the interest of information exchange. The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Department of Transportation or the National Highway Traffic Safety Administration. The United States Government assumes no liability for its contents or use thereof. If trade or manufacturers' names or products are mentioned, it is because they are considered essential to the object of the publication and should not be construed as an endorsement. The United States Government does not endorse products or manufacturers. Drivers often perform non-driving activities that divert their attention from the primary task of driving. This may be due to conversing with a passenger, dialing or hanging up a cell phone, having a phone conversation, or adjusting the radio or other vehicle controls. A driver may also lose focus on driving due to engaging in non-driving cognitive activities, such as being lost in thought or thinking about personal or financial problems. In addition, some crash-associated factors such as driver age and gender, roadway traffic, and environmental conditions may influence a driver's likelihood of engaging in non-driving activities. NHTSA conducted the National Motor Vehicle Crash Causation Survey (NMVCCS) to collect on-scene information on several crash factors, including the ones related to driver inattention. The NMVCCS data was used in this study to look at two facets of distracted driving, namely distraction from sources within the vehicle and non-driving cognitive activities, as associated factors. A descriptive analysis of the weighted data brought out some interesting facts about distracted driving. For example, the results show that, among the crash-involved drivers, distraction from internal sources was more common than distraction due to non-driving cognitive activities. The data also revealed that conversing with a passenger was the most common source of distraction from internal sources, while inattentiveness due to unknown thought focus was the most prevalent factor among the non-driving cognitive activities. Other important patterns detected include the decreasing trend in distraction from internal sources with increasing driver age; the high incidence of drivers under 16 who were thinking about personal problems, and drivers 16 and older who were inattentive due to some unknown thought focus during the pre-crash phase. This report provides necessary details of the NMVCCS data followed by discussion on the choice of the relevant variables and the analysis methodology. The results from univariate and bivariate analyses are discussed in …