US death toll signs increase road deaths
Scheme to deter poor driving appears to have the opposite effect
Electronic highway message boards in the US, which display traffic fatality numbers in a bid to reduce crashes, could be having the opposite effect.
The new study.is overviewed in The Science Journal in the US.
Researchers from the University of Toronto and the University of Minnesota focused on Texas. Officials display messages for one week each month.
The report reveals there were more crashes during the week with fatality messaging compared to the weeks without. What’s more, displaying a fatality message increased the number of crashes by 4.5% over the 10 km following the message boards.
This increase is comparable to raising the speed limit buy 3-5 mph or reducing police presence on highways by 6-14%.
The researchers suggest this “in-your-face” messaging approach weighs down drivers’ “cognitive loads”. This temporarily impacts a driver’s ability to respond to changes in traffic conditions.
“People have limited attention,” said Assistant Professor Joshua Madsen, from the University of Minnesota.
“When a driver’s cognitive load is already maxed out, adding on an attention-grabbing, sobering reminder of highway deaths can become a dangerous distraction.”
The study found the bigger the number in the fatality message, the more harmful the effects. The number of additional crashes each month increased as the death toll rose throughout the year. However, the most additional crashes occurred in January following the messaging of annual road death totals.
Researchers also found that crashes increased when drivers experienced higher cognitive loads. These could be heavy traffic or driving past multiple message boards, but combined with the messaging, the driver seemed less capable of navigating a safe route.
However, the researchers found there was a reduction in crashes when the displayed death tolls were low and when the message appeared where the highways were less complex.
It seems the signs and their messages are acting as a conscious distraction behind the wheel.
Versions of highway fatality messages have been displayed in at least 27 US states.