Driving Riskier with Male Teen Passenger
National Institute of Child Health and Human Development (NICHD)
driversboth males and femaleswere more likely to tailgate
and exceed the speed limit if there was a teenage male passenger
in the front seat, according to a study by the National Institute
of Child Health and Human Development of the National Institutes
male teenagers were less likely to tailgate or exceed the speed
limit when a teenage female was in the front passenger seat.
addition, female teen drivers were slightly more likely to tailgate
if there was a female teen passenger in the vehicle with them.
study was published on-line in Accident Analysis and Prevention
and will appear in a future edition of that journal.
study provides information that will be useful for officials in
devising teen licensing standards," said NICHD Director Duane
Alexander, M.D. "The findings indicate that teen risky driving
increases in the presence of teen passengers, particularly male
teen passengers. But more important, the finding should remind teensand
the adults who care about themthat they need to drive safely,
regardless of who is in the passenger seat."
study was unable to determine why the presence of teen males increased
the likelihood of speeding and tailgating, said the study's first
author Bruce G. Simons-Morton, Ed.D., M.P.H, Chief of NICHD's Prevention
rates for 16- and 17-year-old drivers are higher in the presence
of teen passengers, Dr. Simons-Morton and his colleagues wrote.
However, researchers do not understand the reasons for these higher
crash rates. Dr. Simons-Morton and colleagues at the survey research
firm Westat undertook the current study to learn how the presence
of teen passengers might affect teens' driving behavior.
conduct the study, the researchers positioned observers at the parking
lot exits of 10 high schools in the suburban Washington, D.C. area.
The observers took notes on the make and model of the departing
vehicles, as well as the age and gender of the driver and passengers.
A second group of observers was stationed ½ to ¾ of
a mile away from the parking lot, and used video recording equipment
and a laser-assisted radar device to measure traffic flow. This
second set of observers charted the speed of the vehicles and measured
vehicle headway, an indication of how closely vehicles follow the
vehicles in front of them. The study authors defined vehicle headway
as the time (in seconds) between vehicles as they passed a fixed
point in the roadway.
than 3000 passing vehicles were recorded at the second site. Of
these, 2251 were vehicles in general traffic, and 471 were teen
drivers (245 male and 226 female). No passengers were present in
232 of the teen vehicles, and one or more passengers were present
in 239 of the teen vehicles.
average, teens drove 1.3 miles an hour faster than the general traffic.
Moreover, the average headway for teen drivers was about .17 seconds
shorter than for the general traffic (about 10 feet less at 40 miles
male and female teenage drivers were most likely to drive faster
than the general traffic and to allow shorter headways if there
was a male teenage passenger in the car. In fact, when a male passenger
was in the vehicle, a quarter of teenage drivers exceeded the speed
limit by at least 15 miles an hour.
graph showing the percentage of teenagers driving over 15 miles
an hour is posted at http://www.nichd.nih.gov/new/releases/teenage_drivers_statistics.cfm.)
both male and female teens drove faster and allowed shorter headways
in the presence of a male teenage passenger when compared to teens
who had either no passengers or a female teen passenger. However,
teenage males allowed longer headways in the presence of female
average, headways were .3 seconds shorter for male teens drivers
with male teen passengers, and .15 seconds shorter for female teen
drivers with female teen passengers.
typical driving speeds of around 40 mph, a 0.3 [seconds] difference
is equivalent to traveling slightly more than one car length closer
to the vehicle ahead," the authors wrote.
the article, the study authors explained that although they studied
vehicle headway and speed independently, these two factors are probably
related. "Close following headways may constrain speed; fast
driving may result in close following," they wrote.
this reason, the authors charted the proportion of teens engaging
in some form of risky driving, which they defined as either driving
with a headway of less than 1 second, and speeds 15 or more miles
above the posted speed limit.
to these criteria, of the 14.9 percent of teen males engaging in
risky driving, 21.7 percent had a male teen passenger in the vehicle.
In contrast, only 5.5 percent of teen male drivers showed risky
driving behavior in the presence of a female passenger.
the 13.1 percent of teen female drivers showing risky driving behavior,
12.9 percent had a male teen passenger, and 15.5 percent had a female
passenger. Dr. Simons-Morton said that most cases of risky driving
in this 15.5 percent of risky teen female drivers were due to short
Simons-Morton noted that the current study could not identify why
teens were more likely to engage in more risky driving behavior
in the presence of teen passengers. Teen passengers may distract
the driver or change the driver's attitude or emotion in ways that
are not yet clear. To find answers, he and his colleagues are currently
designing a study that will involve placing electronic monitoring
equipment in vehicles with teen drivers. After learning the reasons
for the risky behavior, researchers can then work to develop ways
to prevent it.
answers become available, Dr. Simons-Morton cautioned parents and
teens to be aware of a tendency that teens appear to have toward
risky driving when other teens are in the vehicle with them, and
to be extra vigilant against unsafe driving under these conditions.
NICHD is part of the National Institutes of Health (NIH), the biomedical
research arm of the federal government. NIH is an agency of the
U.S. Department of Health and Human Services. The NICHD sponsors
research on development, before and after birth; maternal, child,
and family health; reproductive biology and population issues; and