Cell Phone Use as Dangerous as Drunken Driving
Drivers who talk on either handheld or hands-free cellular phones are as impaired as drunken drivers, according to experimental research conducted by Drs. Frank Drews, David Strayer, and Dennis L. Crouch of the University of Utah.
The study reinforced earlier research showing that hands-free cell phones are just as distracting as handheld cell phones
“If legislators really want to address driver distraction, then they should consider outlawing cell phone use while driving.” says Dr. Drews.
Both handheld and hands-free cell phones impaired driving, with no significant difference in the degree of impairment. That “calls into question driving regulations that prohibited handheld cell phones and permit hands-free cell phones,” the researchers write.
Details of the Experiment
This controlled laboratory study included 25 men and 15 women ages 22 to 34 who were social drinkers (three to five drinks per week) recruited via newspaper advertisements. Two-thirds used a cell phone while driving. Each participant was paid $100 for 10 hours in the study.
The driving simulator has a steering wheel, dashboard instruments and brake and gas pedals from a Ford Crown Victoria sedan. The driver is surrounded by three screens showing freeway scenes. Each simulated daylight freeway drive lasted 15 minutes. The pace car intermittently braked to mimic stop-and-go traffic. Drivers who fail to hit their brakes eventually rear-end the pace car. Other simulated vehicles occasionally passed in the left lane, giving the impression of steady traffic flow.
Each study participant drove the simulator during three sessions – undistracted, drunk or talking to a research assistant on a cell phone – each on a different day.
The simulator recorded driving speed, following distance, braking time and how long it would take to collide with the pace car if brakes were not used.
The Utah Highway Patrol loaned the researchers a device to measure blood-alcohol levels.
The study found that compared with undistracted drivers:
- Motorists who talked on either handheld or hands-free cell phones drove slightly slower, were 9 percent slower to hit the brakes, displayed 24 percent more variation in following distance as their attention switched between driving and conversing, were 19 percent slower to resume normal speed after braking and were more likely to crash. Three study participants rear-ended the pace car. All were talking on cell phones. None were drunk.
- Drivers drunk at the 0.08 percent blood-alcohol level drove a bit more slowly than both undistracted drivers and drivers using cell phones, yet more aggressively. They followed the pace car more closely, were twice as likely to brake only four seconds before a collision would have occurred, and hit their brakes with 23 percent more force. “Neither accident rates, nor reaction times to vehicles braking in front of the participant, nor recovery of lost speed following braking differed significantly” from undistracted drivers, the researchers write.
The lack of accidents among the study’s intoxicated drivers may have been because it was conducted in morning hours when participants were well rested. However, most drunken driving accidents occur late at night when drivers are fatigued and their average blood alcohol content (BAC) levels are also twice the legal .08 level used in the research.
"Fortunately, the percentage of drunk drivers at any time is much lower," said Dr. Drews, "So it means the risk of talking on a cell phone and driving is probably much higher than driving intoxicated because more people are talking on cell phones than driving while drunk."
Cell phone users have been found to be 5.36 times more likely to get in an accident than undistracted drivers. Other studies have shown the risk is about the same as for drivers with a 0.08 blood-alcohol level.
Dr. Strayer says he expects criticism “suggesting that we are trivializing drunken-driving impairment, but it is anything but the case. We don't think people should drive while drunk, nor should they talk on their cell phone while driving.”
Drews says he and Dr. Strayer compared the impairment of motorists using cell phones to drivers with a 0.08 percent blood-alcohol level because they wanted to determine if the risk of driving while phoning was comparable to the drunken driving risk considered unacceptable.
“This study does not mean people should start driving drunk,” says Drews. “It means that driving while talking on a cell phone is as bad as or maybe worse than driving drunk, which is completely unacceptable and cannot be tolerated by society.”
The study, was supported by a grant from the Federal Aviation Administration, which is interested in impaired attention among pilots, and was in the summer 2006 issue of Human Factors: The Journal of the Human Factors and Ergonomics Society, 2006 (Summer), 381-391.
- Strayer, D. L., Drews, F. A., and Crouch, D. L. A comparison of the cell phone driver and the drunk driver. Human Factors: The Journal of the Human Factors and Ergonomics Society, 2006 (Summer), 381-391; University of Utah. Drivers on Cell Phones Are as Bad as Drunks: Utah Psychologists Warn Against Cell Phone Use While Driving. University of Utah press release, June 29, 2006; (http://unews.utah.edu/p/?r=062206-1) Pa. should restrict drivers’ cell-phone use. (editorial) Delcotimes.com, July 8, 2006 (http://www.zwire.com/site/news.cfm?newsid=16883506& BRD=1675&PAG=461&dept_id=18168&rfi=6)
- Strayer, D. L., & Johnston, W. A. (2001). Driven to distraction: Dual-task studies of simulated driving and conversing on a cellular phone. Psychological Science, 12, 462-466.
- McCarley, J. S., Vais, M., Pringle, H., Kramer, A. F., Irwin, D. E., & Strayer, D. L. (2001). Conversation disrupts visual scanning of traffic scenes. Paper presented at Vision in Vehicles, Australia.
- Strayer, D. L., Drews, F. A., Albert, R. W., & Johnston, W. A. (2001). Cell phone induced perceptual impairments during simulated driving. In D. V. McGehee, J. D. Lee, & M. Rizzo (Eds.) Driving Assessment 2001: International Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design.
- Strayer, D. L., Drews, F. A. & Johnston, W. A. (2002). Why do cell phone conversations interfere with driving? Proceedings of the 81st Annual Meeting of the Transportation Research Board, Washington, DC.
- Strayer, D. L., Drews, F. A. & Johnston, W. A. (2003). Cell phone induced failures of visual attention during simulated driving. Journal of Experimental Psychology: Applied, 9, 23-23.
- Strayer, D. L., Drews, F. A., & Johnston, W. A. (2003). Are we being driven to distraction? Public Policy Perspectives, Vol. 16, 1-2. (Published by the Center for Public Policy and Administration, University of Utah)
- Strayer, D. L. & Drews, F. A. (2003). Effects of cell phone conversations on younger and older drivers. In the Proceedings of the 47nd Annual Meeting of the Human Factors and Ergonomics Society (pp.. 1860-1864).
- Strayer, D. L. & Drews, F. A. & Crouch, D. J. (2003). Fatal distraction? A comparison of the cell-phone driver and the drunk driver. In D. V. McGehee, J. D. Lee, & M. Rizzo (Eds.) Driving Assessment 2003: International Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design. Published by the Public Policy Center, University of Iowa (pp. 25-30).
- Strayer, D. L., Cooper, J. M., & Drews, F. A. (2004). What do drivers fail to see when conversing on a cell phone? In the Proceedings of the 48nd Annual Meeting of the Human Factors and Ergonomics Society (pp 2213-2217).
- Drews, F. A., Pasupathi, M., & Strayer, D. L. (2004). Passenger and cell-phone conversations in simulated driving. In the Proceedings of the 48nd Annual Meeting of the Human Factors and Ergonomics Society (pp 2210-2212).
- McCarley, J.S., Vais, M.J., Pringle, H., Kamer, A.F., Irwin, D.E., & Strayer, D.L. (2004) Conversation disrupts change detection in complex traffic scenes. Human Factors, 46, 424-436.
- Strayer, D.L., & Drews, F. A. (2004). Profiles in driver distraction: Effects of cell phone conversations on younger and older drivers. Human Factors, 46, 640-649.
- Strayer, D. L. & Drews, F. A. Crouch, D. J., & Johnston, W. A. (2005). Why do Cell Phone Conversations Interfere with Driving? In W. R. Walker and D. Herrmann (Eds.) Cognitive Technology: Essays on the Transformation of Thought and Society (pp. 51-68), McFarland & Company, Inc., Jefferson, NC.
- Strayer, D. L. & Drews, F. A. (In Press). Multi-tasking in the automobile. To appear in A. Kramer, D. Wiegmann, & A. Kirlik (Eds.) Applied Attention: From Theory to Practice
filed under: Drinking and Driving