This investigation studied the effects of 30, 60, and 150 min of continuous driving on drivers' response times to repeated response trials in a simulated emergency-the sudden deceleration of a lead vehicle in a simulated car-following scenario. The results indicated that mean response times of early trials tended to be slower than those of later trials and those of baseline trials. These data imply that repeated response trials can modify decrements nor-mally associated with fatigue mechanisms, and that studies using repeated response trials during driving may not yield valid indications of fatigue-induced performance decrements.

This project developed a prototype integrated system that combines machine vision-based drowsy driver monitoring technology and analysis of operator/vehicle performance parameters to reliably assess driver drowsiness. The purpose of this system will be to reliably quantify commercial motor vehicle driver drowsiness and provide a real-time warning to the driver and/or a control output to the commercial motor vehicle or other systems as warranted. The work performed under the project included: • Survey of the literature associated with the detection and monitoring of bouts of fatigue and drowsiness. • Preliminary focus group research to gather driver preferences for drowsiness feedback and warnings. • Machine vision-based eye closure monitor trade study. Development of an integrated prototype Driver Drowsiness Monitoring System. • On-road evaluation of the Driver Drowsiness Monitoring System.

Based on Coroners ' verdicts, fatigue of car or truck drivers was a contributing factor in 9.1 % of fatal accidents involving trucks. Based on the presence of factors such as extended driving hours, falling asleep at the wheel, comments about tiredness, driving right of centre and night-time driving, the authors estimated fatigue contributed to 19.9 % of the accidents. There were approximately equal numbers of fatigued car drivers and truck drivers. An analysis of casualty and fatal truck accidents by time of day (adjusted for exposure) showed that accident risks were highest during the night on all five Victorian highways studied. Driver fatigue is one of the possible factors underlying this pattern of elevated risk. The report section described in-vehicle fatigue counter-measures. The distinction between fatigue monitors and alerting devices was made and it was recommended that eye closure and head nodding monitors and an alerting device be tested in the next stage of this project. Key Words: Fatigue (human), accident rate, fatality,