March 3, 2006
Posted online April 12, 2006
Study shows cell conversations put drivers
By Tom Woolf
CARBONDALE -- Jacob M. Rose and James E. Hunton want to put a
bug in somebody's ear about distracted drivers, their cell
phones and hands-free devices.
Rose is an associate professor of accounting at Southern
Illinois University Carbondale, and Hunton is an accounting
professor at Bentley College in Waltham, Mass. They are the
authors of a study that contends it's the actual conversation
– regardless of whether you're holding the phone or
talking on a hands-free device – that causes driver
distraction, and therefore, serious accidents.
The bottom line of their study is this: If you are using a
hands-free device with a cell phone, you are four and half times
more likely to be in a serious accident than if you are not
talking on the phone at all.
In fact, that "virtual" conversation is more
distracting than talking with a passenger, their study shows. In
their study, Rose and Hunton suggest that "cell phone
conversations consume significantly more attention than passenger
conversations, resulting in more incidents and crashes during
"Due to the lack of nonverbal cues, conversations on
cellular telephones demand more cognitive resources than
conversations with passengers," the study notes. "More
working memory is consumed by cell phone conversations relative
to passenger conversations, and fewer resources are available for
the driving task."
While Rose and Hunton are accounting professors, both
specialize in studying the effects of technology on learning and
awareness. Their study, "Cellular Telephones and Driving
Performance: The Effects of Attentional Demands on Motor Vehicle
Crash Risk," appeared late last year (October) in Risk
Analysis, the journal of the Society for Risk Analysis. Rose
noted the researchers received no outside funding for their
"What we're trying to figure out is if there is a way
we can reduce accident rates and deaths through some kind of
driver training," Rose said. "The reason we're
looking at this is because of the number of countries and cities
that have started to ban handheld phones, such as all of
Australia, a lot of Europe and some cities in the U.S. Our
evidence and the evidence of other studies that have come out
recently have said those bans won't do any good because
it's just as distracting to be on a hands-free
"It's the actual conversation," Rose said.
"If you go back to basic psychology research, you find a few
things that suggest conversing is far more demanding than
listening, because you have to understand what's being said
to you and then prepare for your reply. Having a conversation is
In their experiment, drivers with and without communication
training completed a simulated city driving course while engaged
in one of three conversation modes: no conversation, conversation
with a passenger and conversation on a hands-free cell phone.
Fifty-six pilots and 55 non-pilots participated in the study.
Trained questioners carried on the same conversations with all
the study participants.
Hunton is also a pilot and pilot instructor. He and Rose chose
airline pilots as the perfect "trained" study
participants, since they safely fly airplanes while physically
talking to crew members and virtually conversing over the radio
with air traffic controllers – behavior the authors believe
is similar to talking with a passenger and on a cell phone while
Key findings included:
• When not involved in a conversation, the driving
performance of pilot-drivers and non-pilot-drivers was
• When talking with a passenger, the performance of
pilot-drivers was superior to non-pilot-drivers.
• When talking on a cell phone, the performance of
pilot-drivers deteriorated slightly, but the performance of
non-pilot-drivers dropped sharply.
"Whatever the topic of conversation is, you're
processing it very actively," Rose said. "The cell
phone industry has basically said, ‘Look, you talk to
passengers all the time, and we can't ban that, so why should
we ban phones?' We experimentally investigated this issue and
compared speaking to a passenger versus speaking on a hands-free
phone. We found the accident rates were more than twice as high
when you're on a hands-free phone versus talking to a
passenger for the exact same conversation."
"The real issue seems to be when you lack all of the
non-verbal cues of a close-contact conversation, the conversation
is that much more demanding," Rose explained. "Some
research suggests that 90 percent or more of a conversation is
actually non-verbal. It uses a huge amount of your attention to
try to deal with the fact that you're missing all those
The study presents the first evidence to dispel what Rose
called the "myth" that talking on a cell phone or
hands-free device is no different than speaking to a
"It is, and it's more dangerous," he said.
The researchers looked at what pilots do differently compared
to non-pilots. They found that non-pilots try hard to visualize
the person they are speaking to on a cell phone, while pilots do
not. Non-pilots also said they try to imagine the gestures and
non-verbal cues of the people they are speaking with on a cell
phone, while again, pilots do not.
The answer, Rose and Hunton contend, is training.
"Most people would say they don't need that, and our
drivers thought that as well," Rose said. "We had
people in our simulators hitting two or three cars and
pedestrians in one sitting, because we programmed a difficult
driving course. We also measured smaller things, like running red
lights and missing traffic signs, and those rates are even higher
than the serious accident rates."
They propose that instead of an outright ban on cell phones
and hands-free devices, governments require drivers to complete
an endorsed training program.
"Basically it's a ban unless you get the
training," Rose said. "States or cities would have to
say ‘you have until this date to come and do the training
and get the certification because we know it's going to
reduce the chances that you will have an accident.'"
He acknowledges that there are some researchers who are upset
with their conclusions because the study could be interpreted to
suggest an outright ban on wireless communication. However, Rose
also emphasizes that their study differs significantly from other
research on the topic.
"This is the only study that has looked at the training
issue, the only study that has looked at how we can reduce
accidents, the only study that has looked at whether it is
different speaking to a passenger versus talking hands
free," he said. "This is one of the few studies
actually using lab experiments versus studying accident
The researchers' next step is to design and test a
short-term training program for drivers.
"People tend to believe, especially after hearing about
laws banning cell phone use in cars, that they can put their
headset on and it has no effect on them," Rose said.
Leading in research, scholarly and creative activity is
among the goals of Southern at 150: Building Excellence Through
Commitment, the blueprint the University is following as it
approaches its 150th anniversary in 2019.
(Caption: Cell phone safety – Jacob M. Rose, an
associate professor of accounting at Southern Illinois University
Carbondale, is co-author of a study that contends it’s the
actual conversation – regardless of whether you’re
holding the cell phone or talking on a hands-free device –
that causes driver distraction, and therefore, serious
Photo by Russell Bailey