Queensland University
of Technology
Talking hands-free on
a mobile phone while driving is just as distracting as a conversation using a
hand-held phone, despite one being illegal and the other not, a QUT road safety
study has found.
Dr Shimul (Md
Mazharul) Haque, from QUT's School of Civil Engineering and Built Environment
and Centre for Accident Research & Road Safety -- Queensland (CARRS-Q),
presented findings at a Driving Distraction Seminar held at QUT in November.
As part of the study,
Dr Haque measured the effects of mobile phone distraction on safety including
reaction time and driving performance in the CARRS-Q Advanced Driving
Simulator.
"We took a group of drivers and exposed them to a virtual road network which included a pedestrian entering the driver's peripheral vision from a footpath and walking across a pedestrian crossing," Dr Haque said.
"We then
monitored the driver's performance and reaction times during hands-free and
hand-held phone conversations and without.
"The reaction
time of drivers participating in either a hand-held or hands-free conversation
was more than 40 per cent longer than those not using a phone.
"In real terms
this equates to a delayed response distance of about 11m for a vehicle
travelling at 40km/h.
"This shows
hands-free and hand-held phone conversations while driving have similar
detrimental effects in responding to a very common peripheral event of a
pedestrian entering a crossing from the footpath."
Dr Haque said it was
the cognitive load required to hold a conversation that was the distraction,
not whether or not the driver was holding a phone.
"It appears that
the increased brain power required to hold a phone conversation can alter a
drivers' visual scanning pattern.
"In other words
the human brain compensates for receiving increased information from a mobile
phone conversation by not sending some visual information to the working
memory, leading to a tendency to 'look at' but not 'see' objects by distracted
drivers.
"The distraction
of a mobile phone conversation is not the same as an in-car conversation with a
passenger because the non-driver can alter their dialogue based on the driving
environment, for example stop talking when approaching a complex driving
situation.
Dr Haque said this
raised a serious question on the appropriateness of mobile phone use laws while
driving in Queensland, which only impose a ban on hand-held mobile phone use
but allowed drivers to use mobile phones with a hand-free device.
He said in addition,
the study also found the reaction time of provisional licence holders was
double compared to those who held an open licence.
"Despite
provisional licence holders in this study averaging a driving experience of
more than two years, the detrimental effects of mobile phone distraction showed
P-plate drivers had an increased probability of failing to detect a
pedestrian."
Dr Haque said the
distraction of mobile phone use also had an impact on driver braking behaviour.
"Distracted
drivers on average reduced the speed of their vehicle faster and more abruptly
than non-distracted drivers, exhibiting excess braking," he said.
"While the driver
is likely to be compensating for the perceived risk of talking and driving, the
abrupt or excessive braking by distracted drivers poses a safety concern to
following vehicles.
"Again these
findings highlight a need to consider mobile phone use laws in response to
interventions to reduce rear-end crashes."