title: Driving with a partially autonomous forward collision warning system: how do drivers react?
abstract: OBJECTIVE
  The effects of a forward collision warning (FCW) and braking system (FCW+) were examined in a driving simulator study analyzing driving and gaze behavior and the engagement in a secondary task.
  
  
  BACKGROUND
  In-depth accident analyses indicate that a lack of appropriate expectations for possible critical situations and visual distraction may be the major causes of rear-end crashes. Studies with FCW systems have shown that a warning alone was not enough for a driver to be able to avoid the accident. Thus,an additional braking intervention by such systems could be necessary.
  
  
  METHODS
  In a driving simulator experiment, 30 drivers took part in a car-following scenario in an urban area. It was assumed that different lead car behaviors and environmental aspects would lead to different drivers' expectations of the future traffic situation. Driving with and without FCW+ was introduced as a between-subjects factor.
  
  
  RESULTS
  Driving with FCW+ resulted in significantly fewer accidents in critical situations. This result was achieved by the system's earlier reaction time as compared with that of drivers. The analysis of the gaze behavior showed that driving with the system did not lead to a stronger involvement in secondary tasks.
  
  
  CONCLUSIONS
  The study supports the hypotheses about the importance of missing expectations for the occurrence of accidents. These accidents can be prevented by an FCW+ that brakes autonomously.
  
  
  CONCLUSIONS
  The results indicate that an autonomous braking intervention should be implemented in FCW systems to increase the effectiveness of these assistance systems.
authors.affiliation: TU Braunschweig, Department of Traffic and Engineering Psychology, Gausstrasse 23, 38106 Braunschweig, Germany. Elke.Muhrer@tu-bs.de
authors.forename: Elke
authors.initials: E
authors.lastname: Muhrer
authors.forename: Klaus
authors.initials: K
authors.lastname: Reinprecht
authors.forename: Mark
authors.initials: M
authors.lastname: Vollrath
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control* / Q000523:psychology; D000328:Adult; D059031:Anticipation, Psychological; D001288:Attention; D001334:Automobile Driving / Q000523:psychology*; D001336:Automobiles; D003198:Computer Simulation; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D011482:Protective Devices; D011930:Reaction Time; D014584:User-Computer Interface; D014796:Visual Perception; D055815:Young Adult