title: Effects of fatigue on driving performance under different roadway geometries: a simulator study.
abstract: OBJECTIVE
  This article examines the effects of fatigue on driving performance under different roadway geometries using a driving simulator.
  
  
  METHODS
  Twenty-four participants each completed a driving scenario twice: while alert and while experiencing fatigue. The driving scenario was composed of straight road segments and curves; there were 6 curves with 3 radius values (i.e., 200, 500, and 800 m) and 2 turning directions (i.e., left and right). Analysis was conducted on driving performance measures such as longitudinal speed, steering wheel movements, and lateral position.
  
  
  RESULTS
  RESULTS confirmed that decremental changes in driving performance due to fatigue varied among road conditions. On straight segments, drivers' abilities to steer and maintain lane position were impaired, whereas on curves we found decremental changes in the quality of longitudinal speed as well as steering control and keeping the vehicle in the lane. Moreover, the effects of fatigue on driving performance were relative to the radius and direction of the curve. Fatigue impaired drivers' abilities to control the steering wheel, and the impairment proved more obvious on curves. The degree varied significantly as the curve radius changed. Drivers tended to drive closer to the right side due to fatigue, and the impairment in maintaining lane position became more obvious as the right-turn curve radius decreased.
  
  
  CONCLUSIONS
  Driver fatigue has detrimental effects on driving performance, and the effects differ under different roadway geometries.
authors.affiliation: a Key Lab of Traffic Engineering , Beijing University of Technology , Beijing , P. R. China.
authors.forename: Hongji
authors.initials: H
authors.lastname: Du
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhao
authors.forename: Xingjian
authors.initials: X
authors.lastname: Zhang
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Rong
mesh_terms: D000328:Adult; D001334:Automobile Driving / Q000523:psychology* / Q000706:statistics & numerical data; D003198:Computer Simulation; D004779:Environment Design / Q000706:statistics & numerical data*; D005221:Fatigue / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: driving performance; driving simulator; fatigue driving; roadway geometry