title: Looming auditory collision warnings for driving.
abstract: OBJECTIVE
  A driving simulator was used to compare the effectiveness of increasing intensity (looming) auditory warning signals with other types of auditory warnings.
  
  
  BACKGROUND
  Auditory warnings have been shown to speed driver reaction time in rear-end collision situations; however, it is not clear which type of signal is the most effective. Although verbal and symbolic (e.g., a car horn) warnings have faster response times than abstract warnings, they often lead to more response errors.
  
  
  METHODS
  Participants (N=20) experienced four nonlooming auditory warnings (constant intensity, pulsed, ramped, and car horn), three looming auditory warnings ("veridical," "early," and "late"), and a no-warning condition. In 80% of the trials, warnings were activated when a critical response was required, and in 20% of the trials, the warnings were false alarms. For the early (late) looming warnings, the rate of change of intensity signaled a time to collision (TTC) that was shorter (longer) than the actual TTC.
  
  
  RESULTS
  Veridical looming and car horn warnings had significantly faster brake reaction times (BRT) compared with the other nonlooming warnings (by 80 to 160 ms). However, the number of braking responses in false alarm conditions was significantly greater for the car horn. BRT increased significantly and systematically as the TTC signaled by the looming warning was changed from early to veridical to late.
  
  
  CONCLUSIONS
  Looming auditory warnings produce the best combination of response speed and accuracy.
  
  
  CONCLUSIONS
  The results indicate that looming auditory warnings can be used to effectively warn a driver about an impending collision.
authors.affiliation: School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. r.gray.2@bham.ac.uk
authors.forename: Rob
authors.initials: R
authors.lastname: Gray
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control*; D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D001288:Attention; D001307:Auditory Perception; D001334:Automobile Driving; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008297:Male; D011482:Protective Devices; D011930:Reaction Time; D055815:Young Adult