A driver concentrating on a cell-phone call is more likely to be a hazard on the highway than one who is driving drunk, a University of Utah study says. Whether the cell phone is hand-held or used hands-free, the driver's attention is diverted and the distraction can cause problems, the study says.
The research is the work of David Strayer and Frank A. Drews of the U. psychology department and Dennis J. Crouch, a toxicologist. It is based on the performance of 41 test subjects who performed simulated driving tasks on the university's driving simulator.
In conditions simulating freeway conditions, they were put through their paces in a single-task mode (with no apparent distractions) while using a cell phone and with a blood alcohol level of .08, the level at which drunkenness is assumed in most states.
"Cell phone conversation draws attention away from the processing of the visual environment," Strayer told a Park City safety conference audience this week. "We found a 50 percent reduction in the processing of visual information when you're driving and talking on a cell phone."
In the study, the cell phone users had more rear-end collisions and their responses to a vehicle slowing in front of them were 8 percent slower, the study found. They tended to try to compensate by driving "sluggishly," the study indicated, taking 15 percent longer to return to their initial driving speed.
The research, likely to be published in a scholarly journal, could be fuel for a growing movement to make driving while using a cell phone illegal. Several states and local jurisdictions already have enacted laws to curb phone use by drivers. The 2002 Utah Legislature saw some proposed cell-phone-related laws, but the sponsors couldn't get enough support to push them through.
Rep. Chad Bennion, R-Murray, reached in California where he is attending meetings related to his legislative work, said he would "really like to take a look at that report. It's hard to know how to respond without knowing the details." He said his experience in trying to determine if laws are needed to regulate cell phone use in cars proved what a difficult issue it is. Trying to legislate "good sense" is not easy, he said.
Debates on the topic are clouded by the fact that many drivers do other things while driving that can be distracting, including eating, putting on makeup, shaving, combing their hair or trying to read or write, Bennion said. "I see them all the time." Also, individual abilities to perform more than one task at a time is a factor, he said.
The Utah study also "found equivalent impairment" for drivers who used "hands-free" devices to be basically the same for those who were holding their phones. That may "call into question driving regulations that prohibit hand-held cell phones and permit hands-free cell phones," an abstract of the study says.
The impairments noted between the cell-phone users and subjects who were legally drunk were different.
"With respect to traffic safety, our data indicate that, when controlling for driving difficulty and time on task, cell-phone drivers exhibit greater impairments — more accidents and less responsive driving behavior," the abstract says. Drunken drivers applied 20 percent greater braking pressure when faced with a slowing car in front, the researchers found.
The Utah study corroborates research done in Toronto, which concluded that both drunken driving and cell-phone use while driving increased the risk of collision by three to six times.
The U.S. National Highway Traffic Safety Administration estimates that driver distraction is a factor in 20 percent to 30 percent of the 6 million car crashes in the United States every year.
But the figures do not always agree. Based on mathematical models, Harvard University estimated that 2,600 auto deaths could be attributed to phone use, while the NHTSA reported that 17,419 people died last year in alcohol-related accidents. Supporters of the telecommunications industry cite such discrepancies and say that simulators are not a good way to gauge how much cell-phone use influences driving results.
E-mail: tvanleer@desnews.com