The existence and impact of the Psychological Refractory Period effect in the driving environment

Driver distraction from in-vehicle tasks can have negative impacts on longitudinal and lateral vehicle control. The distraction problem is increasing due to advances in the functionality, availability, and number of in-vehicle systems. One approach to a solution is managing in-vehicle task presentation to reduce associated distraction. This paper reports three driving simulator experiments, designed to investigate the existence of the Psychological Refractory Period in the driving context and its effect on driver performance. The first two studies demonstrate that the effect is present when one or two surrogate in-vehicle tasks are presented in close temporal proximity to a lead vehicle braking event. Brake responding is subject to an increasing delay as the interval to an in-vehicle task is decreased. In-vehicle task modality and task presentation order modulate this effect. The final study will investigate whether the Psychological Refractory Period exists for a range of safety-critical driving events such as lead vehicle decelerations, swerving away from an out-of-control vehicle, and performing a lane-change manoeuvre. The advances on prior work include the use of an advanced driving simulator, and presentation of unpredictable safety-critical events and real-world in-vehicle tasks. The results have implications for the management of in-vehicle distractions – and driver safety; specifically through controlling the timing and modality of task presentation.