The study involved 41 drivers willing to test the effects of engaging in other distracting activities while they drive. Participants first demonstrated their driving ability in three key areas: lane keeping, speed contro, and quick response to a changing traffic light. Next, they demonstrated these abilities while also performing a relatively easy distracting activity (recalling, adding and repeating simple numbers presented while driving) and a relatively difficult one (developing and asking yes-or-no questions to identify an object while driving). Researchers expected that the more difficult activity would require more thought and thereby distract drivers more significantly from safe driving.
Indeed, results showed that the more difficult activity reduced driving safety more than the easier one. Yet they also showed that drivers did not recognize one activity as more difficult than the other and estimated no difference between the activities' affect on their driving abilities. According to Horrey and his researchers, these results, combined with previous studies, suggest that drivers are not aware of their own performance loss due to distraction.
"Today it is important to understand how new in-vehicle tasks affect drivers' performance as well as how they affect drivers' perceptions of their own performance," the study concludes, noting that commercial drivers frequently have to deal with other distracting activities as part of their jobs, and the high cost of crashes to employers. The study also outlines the steep costs to employers of off-the-job crashes due to distracted driving, compounded by a national increase in the length of daily commuting times.
Cell Phones and Driving
NSC President and CEO Janet Froetscher identified cell phone use while driving as one of America's most urgent traffic safety issues. In January, NSC became the first national organization to call for a total ban on that activity, based on scientific estimates that cell phone use while driving contributes to 6 percent of crashes, or 636,000 crashes, 330,000 injuries, 12,000 serious injuries and 2,600 deaths each year. The same research put the annual financial toll of cell phone-related crashes at $43 billion.
"Our nation has reached a point where we estimate more than 100 million people are engaging in this dangerous behavior daily," Froetscher said, adding that the issue is not the type of phone a driver uses, rather it is the distraction caused by the conversation. "Hands-free devices do not make cell phones any safer. Several studies indicate that the principle risk is the cognitive distraction. Studies also show that driving while talking on a cell phone is extremely dangerous and puts drivers at a four-times greater crash risk."
To work toward improving driving safety, the study calls for more research on drivers distracted by activities of different degrees of difficulty, in both laboratory and naturalistic settings.
The study was led by William J. Horrey of the Liberty Mutual Research Institute for Safety.