As the National Highway Traffic Safety Administration’s (NHTSA) latest published review of the current state of knowledge of driver distraction (April 2008) so aptly puts it, “Cell phones are the contemporary icon of driver distraction.” What the review tells us, however, is that distraction is difficult to define, difficult (if not impossible) to measure, and that cell phones are only one of many distractions—which is not to deny that they are a big problem, likely even a bigger problem than other common in-vehicle tasks involving as they do “a relatively extended period of exposure” engaging both cognition and emotions.
The discussion of the lack of a generally accepted definition of distraction serves as a reminder of how challenging it is to stay focused on the driving task. The first-cited definition: “Distraction is attention given to a non-driving-related activity, typically to the detriment of driving performance” seems adequate enough. But it goes on to distinguish between events or activities internal and external to the vehicle.
Internal events include any ‘triggering activity’ which the driver may or may not initiate or have control over, any cognitive distraction, emotional upset or preoccupation, and even involuntary actions such as sneezing, coughing or itching. External events include sudden, unexpected movements by wild animals, or being temporarily blinded by the sun or oncoming headlights, or being startled by emergency sirens. Advertising signage is also mentioned as a potentially important source of [external] distraction becoming “both more prevalent and more dynamic and thus potentially more effective at capturing drivers’ attention in certain areas.”
The review discusses the difficulty of accurately determining in any particular case whether driver distraction or any other form of inattention was a contributing factor in a crash. In crash-based studies, direct evidence of a distracting activity is rarely found and the review notes, “Drivers are understandably reluctant to admit that they were engaged in a secondary task, particularly if that involvement may have contributed to the crash.” As a result it is generally thought that the incidence of distraction among crash-involved drivers is underestimated.
The top recommendations of the review for future research are for a larger more representative study to better understand trends in driver distraction and better estimates of the incidence of distraction in crashes.
The review notes that the difficulties in defining, observing and measuring distraction hamper the development of effective countermeasures. In other words without an accurate enough definition of the nature and scope of the problem, devising solutions is also difficult. The review notes that, “the obvious way to reduce distracted driving is to convince or require drivers to pay attention to their driving.
Behavioral strategies to reduce distracted driving include attempting to remove underlying causes and promoting awareness of the risks (NHTSA, 2006).” But it also implies that we are still a long way from finding many distracting activities including eating, drinking and listening to music while driving, socially unacceptable. At this point, it observes, “other than cell phone laws, there are no laws that address driver distraction explicitly.”