Reliability of simulator driving tool for evaluation of sleepiness, fatigue and driving performance

Abstract

Study objective: To compare the impact of extended wakefulness (i.e., sleepiness) and prolonged driving (i.e., fatigue) at the wheel in simulated versus real-life driving conditions.

Design: Participants drove on an INRETS-MSIS SIM2 simulator in a research laboratory or an open French highway during 3 nocturnal driving sessions. A dose-response design of duration of nocturnal driving was used: a 2 h short driving session (3-5 AM), a 4 h intermediate driving session (1-5 AM) and an 8 h long driving session (9 PM-5 AM).

Participants: Two groups of healthy male drivers (20 for simulated driving and 14 drivers for real driving; mean age±SD=22.3±1.6 years), free of sleep disorders.

Measurements: Number of inappropriate line crossings, self-rated fatigue and sleepiness were recorded in the last hour of driving sessions to control the effects of prior waking time and time of day.

Results: Compared to the daytime reference session, both simulated and real driving performance were affected by a short nocturnal driving session (P<.05 and P<.001, respectively). Extension of nocturnal driving duration affected simulated performance nonlinearly and more severely than that of real driving (P<.001). Compared to the daytime reference session, short nocturnal simulated and real driving sessions increased self-perceived fatigue and sleepiness. Real and simulated driving conditions had an identical impact on fatigue and sleepiness during extended periods of nocturnal driving.

Conclusions: In healthy subjects, the INRETS-MSIS SIM2 simulator appropriately measures driving impairment in terms of inappropriate line crossings related to extended wakefulness but has limitations to measure the impact of extended driving on drivers' performance.