Effects of unreliable automation and takeover time budget on young drivers’ mental workload

Young drivers are involved in a significantly higher number of crashes than any other age group. Highly automated vehicles are expected to improve traffic safety and reduce human errors; however, driver needs to take over in situations where the automation fails. A driving simulation study was conducted with twenty-eight young drivers to investigate the effects of unreliable automation, different takeover time budgets (TOTBs), and secondary tasks on mental workload during takeover situations. Mental workload was measured using a combination of physiological and secondary task performance measures. Results suggested that when faced with critical incidents, young drivers experienced lower mental workload under 10s of TOTB as compared to 5s or 8s of TOTB especially when they were engaged in a demanding secondary task. In addition, drivers experienced higher mental workload when regaining the control of the vehicle in the automated mode than the manual driving condition.