How cognitive distraction affects motorway short-term work zone safety along curves: A driving simulation study

This study investigates how cognitive distraction affects driver behaviour on a two-lane motorway reduced to one lane (the left) in a short-term work zone along a left-hand curve. Forty-two participants were divided into two groups: undistracted and cognitively distracted drivers - with the latter required to perform mental calculations. Drivers had to react to the sudden and unexpected appearance of stationary vehicles in a queue. Distracted drivers started braking at higher speeds and released the accelerator later than undistracted ones. Their reaction times were significantly longer, and five of them could not avoid a collision with the last vehicle in the queue. Heat maps of eye fixations show that distracted drivers focused their gaze on a few elements of the road section, predominantly on the inside of the carriageway, while undistracted drivers looked at a wider area of the road scenario. Distracted drivers exhibited delayed responses to unexpected events, highlighting the importance of addressing cognitive distraction in road work zones. Given the high frequency of roadworks on motorways, specific safety countermeasures are needed to compensate for the objective risk posed by unexpected events in scenarios where distracted drivers operate with limited available sight distance.