Drowsy and Distracted Drivers

Section II

Introduction

The six major areas of the AASHTO Strategic Highway Safety Plan—drivers, vehicles, special users, highway, emergency medical services, and management—are subdivided into 22 goals, or key emphasis areas, that impact highway safety. One of these areas addresses reducing crashes and fatalities caused by inattentive drivers.

NHTSA has identified driver inattention as a causative factor in 25–30 percent of crashes (Wang, Knipling, and Goodman, 1996). An inattentive driver may be temporarily distracted by something inside or outside the vehicle, may be drowsy or fatigued, or may simply have his or her mind on something other than driving. Crashes involving drivers who have fallen asleep at the wheel are especially likely to result in serious or fatal injuries.

The focus of this guide is on reducing collisions due to driver distraction or fatigue. There are several challenges to accomplishing this goal. One is that available crash data do not fully document the problem of distracted and fatigued driving. Although most state crash report forms capture some level of information on whether a driver has fallen asleep at the wheel, only recently have states begun collecting data on distraction as a causative factor in crashes. There is only limited information available on the sources of driver distraction, and the reliability of the data has not been demonstrated. Unlike the case with alcohol, there is no objective way of identifying whether someone is too drowsy or too distracted to drive. In general, crash data are thought to significantly underestimate the contribution of distracted and drowsy driving to crashes.

Another challenge is that the reduction of crashes and fatalities due to distracted and drowsy driving necessitates change in driver behavior. Some success can be achieved by improving roadways and vehicles to make them more forgiving and by incorporating new technologies to alert an inattentive driver. Ultimately, however, we must change drivers themselves so that they are less likely to operate their vehicles when drowsy or distracted. This task is made all the more challenging by the simple fact that virtually everyone, at some point, drives while fatigued or while engaging in potentially distracting behaviors.

This emphasis area encompasses a broad mix of behaviors that exhibit themselves in all population groups, on all types of roadways, in all types of vehicles, and under all driving conditions. Addressing the problem will necessarily require a broad-based, comprehensive approach. Roadway design and traffic operations engineers, planners, law enforcement, driver licensing officials, and road safety advocates in both the public and private sectors all have important roles to play in reducing the number of crashes due to inattentive driving.