Hands-on or hands-free, using a cell phone while driving is not safe

In 2003 cell phone distraction resulted in 2,600 deaths and 330,000 injuries

Ninety percent of cell phone owners report that they use the phone while driving, according to a report published in 1999. Another report from 2003 indicates that cell phone distraction results in 2,600 deaths, 330,000 injuries, and 1.5 million instances of property damage in the United States each year. Can hands-free devices reduce accidents, fatalities, or damage? No, say human factors researchers published in a special driver distraction section in Human Factors: The Journal of the Human Factors and Ergonomics Society.

In fact, if a hands-free device is not easy to use, a driver who uses it could be even more distracted than by simply holding the phone. Things could get worse: The next generation of communication technology — such as wireless Internet, speech recognition systems, satelitte radio, and e-mail — could be far more distracting for drivers, creating even greater risk on the road.

The recent controversy regarding cellular telephones and their effect on driving safety has generated public concern regarding the danger posed by these devices. Many state legislatures have responded with various proposals to restrict cell phone use while driving. But some of the laws proposed won’t improve driver safety because they don’t discourage hands-free phone use.

The debate surrounding new technologies in vehicles has indicated a substantial need for a better technical basis to support public policy. This, coupled with a recent surge of research in this area, motivated the special section of Human Factors (Volume 46, Number 4, Winter 2004).

The eight driver distraction special section papers show that

• Cell phone conversations alone, without dialing or answering, change the way drivers see the world and make them more likely to miss traffic signs and other important information (see the special section papers by McPhee, Scialfa, Dennis, Ho, and Caird and by Atchley and Dressel).
• Using a speech recognition system to reduce distraction, such as speaking an address into a navigation system, can make the task easier, but it can still disrupt driving, particularly the driver’s ability to control the vehicle’s speed. Drivers slow down when entering information manually or by voice (see the paper by Tsimhoni, Smith, and Green).
• Information (such as telephone numbers) presented by voice competes for drivers’ attention to a far greater extent than when the driver sees the same information presented on a display. Horrey and Wickens found that auditory information led to poorer speed control than was the case with visual displays of the same information.
• The effect of distractions depends on when they occur. Interruptions to driving, such as answering a cell phone, are likely to be more dangerous if they occur during maneuvers like merging to exit a freeway (refer to the paper by Monk, Boehm-Davis, and Trafton).

Overall, these results show that hands-free devices are not the solution to the problem of driver distraction. The papers also indicate new directions for enhancing driving safety.