More evidence against cell phones and driving
Research Urges Drivers to Put Down the Cell Phone
Many of us use our cell phones while driving. We try to be careful. We
keep our eyes on traffic and try to maintain a safe distance from the
car in front of us while we talk on the phone. There’s no harm, right?
Two researchers at North Carolina State University have evidence to
In a recent scientific study, Dr. David Kaber, associate professor of
industrial engineering, and doctoral student Ruiqi Ma examined the
effects of cell phone use and in-vehicle automation on driver
situation awareness (SA) and driving performance through the use of a
PCbased driving simulator. The results of their study recently
appeared in the International Journal of Industrial Ergonomics (Vol.
35, No. 10).
They found that the use of adaptive cruise control (ACC) – a new
technology that automatically adjusts vehicle speed to maintain a
user-defined distance from the vehicle directly ahead of it – under
normal driving conditions facilitated SA by relieving the drivers’
workload, which may have allowed them to pay more attention to the
driving environment. The study also showed that cell phone use was
detrimental to driver SA with and without ACC.
“The ACC provides good benefits in terms of workload relief, but cell
phone use directly counters that,” Kaber said. The impact is
particularly apparent in the driver’s ability to make projections on
the developing driving situation, he added.
Eighteen NC State graduate students, ages 21 to 35, participated in
the study. All participants drove a virtual car in a three-dimensional
simulation of a typical four-lane-highway driving environment under
normal conditions. Wearing stereographic goggles to view a simulation
displayed on a personal computer, participants used a realistic
steering wheel, gas pedal and brake pedal to change speed and position
as they maneuvered the virtual highway. During the simulations, the
participants had to stay behind a lead car and maintain a safe
distance from it.
Half of the participants answered cell phone calls as secondary
distracter tasks, and all drove with and without adaptive cruise
control. Participant driving performance – staying in the lane and
keeping a safe distance behind the lead car – was tracked by the
computer. The participants’ SA was assessed by way of a series of
questions randomly posed during simulation freezes.
Kaber and Ma had two goals for this study. The first was to
investigate the effects of cell phone use and adaptive cruise control
in driving on SA, and perceived driver workload using objective
measures. “We wanted to identify if there was a potential benefit of
ACC under normal driving circumstances when a person is multitasking,”
Kaber said. The second goal of the study was to assess the effect of
competing driving and communication tasks on driving performance.
Kaber and Ma drew on empirical studies of SA in aviation to devise an
operational definition of SA in driving. Kaber explained that there
are three components of SA: perception, comprehension and projection
of the environment. They translate to “What is it? What does it mean
to me? What will this information mean to me in the future?” Kaber
Although there have been some studies of SA in driving, Kaber pointed
out that “Those
studies made inferences on the basis of performance measures, looking
at people’s overt driving behavior and trying to project what’s
happening for them cognitively. What Ruiqi [Ma] has done here was to
define an objective measure of situation awareness in the context of a
driving task in order to directly describe people’s cognition or what
they know at any given time during the simulation. Ruiqi conducted a
cognitive task analysis to identify all the potential goal states of a
driver under normal circumstances.”
From this cognitive task analysis, Kaber and Ma devised a series of
questions that would ascertain the SA of participants during the
simulations instead of inferring SA from driving performance measures.
“If [the participants] were perceiving, comprehending and projecting,
they would be able to answer our questions correctly,” Kaber said. “If
they were not, they got them wrong.”
Although Kaber and Ma saw a trend toward worse headway maintenance
(distance between vehicles) and lane deviation when a cell phone was
used, more research is needed. “It is important to note that Ruiqi
made three phone calls during the driving trial and those [calls] were
separated by seven to 10 minutes. To see the impact of cell phone use
on driving performance, in future studies we might have the
participants talk on the cell phone the whole time,” Kaber explained.
“The important thing is cell phone use negatively impacts situational
situational awareness has been linked to effective decision-making and
performance,” Kaber added. “People may say ‘I’m using my cell phone,
and I can brake in time’ or ‘I can keep my car in the lane’ or ‘I can
maintain my speed,’ but the problem is that it is having an impact on
their attentional resources. It compromises their overall awareness of
the driving environment, and when a critical condition develops, they
may not be prepared to deal with it.”
In other words, hang up, drivers.
Source: North Carolina State University
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