Analysis of Driver Visual Behaviour in Highway Work Zones through Driving Simulator

Highway work zones are known to carry a higher crash risk than comparable road sections without ongoing works, and there is growing evidence that this risk is linked to the visual and cognitive demands the work zone places on the driver rather than to its altered geometry alone. Several existing studies compare a single work zone against an open road baseline, so little is known about how that demand changes as the work zone becomes more restrictive. The aim of this thesis is to describe how drivers distribute their visual attention along a sequence of highway work zones of increasing complexity, and to identify the strategy by which they adapt to them. Twenty-two licensed drivers completed a single continuous drive on a fixed-base driving simulator along a three-lane motorway containing three work zones of increasing restriction, separated by two ordinary signed motorway sections. Gaze was recorded with wearable eye-tracking glasses and subjective workload with the NASA-TLX questionnaire, and fixation, saccade and pupillary measures were compared across the five road sections. Visual sampling became denser as the work zone became more restrictive, both in fixations and in saccades, and the work zone sections were clearly distinguishable from the sections without a work zone on these measures. The rate at which the eye generated fixations and saccades, however, changes poorly; what changed most was the driving speed, which fell steadily as restriction increased. The results suggest that driver’s may absorb the additional visual demand of a work zone by slowing down, which has direct implications for the design and speed management of temporary traffic schemes.