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
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
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
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
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&
- Strayer, D. L., & Johnston, W. A. (2001).
Driven to distraction: Dual-task studies of simulated driving and
conversing on a cellular phone. Psychological Science,
- 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
- 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,
- 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,
- 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