Driving on a busy highway with lane changes is more mentally taxing than going down a straight stretch of empty roadway. People’s attention spans are short. When a driver’s cognitive load is high, adding an attention-grabbing, depressing reminder of highway deaths can be dangerous.
The researchers determined that the higher the number in the fatality message, the more damaging the impacts. As the death toll rose throughout the year, extra crashes increased month by month. The most crash occurred in January when the message announced the annual total. They also discovered that crashes were more common in regions with higher cognitive burdens, such as heavy traffic or driving past several message boards.
Compared to weeks without fatality messages, there were more accidents during the week with fatality messaging. In addition, the messages seemingly increased the mortality rate by 4.5% over the 10 km (6.21 mi) following the message. According to their findings, fatality messages cause 2,600 crashes and 16 deaths in Texas every year, costing $377 million.
Perhaps similar efforts could be recreated to reach drivers in a safer manner, such as when they are stopped at a junction so that their attention stays on the road.