The Influence of Fog on Motion Discrimination Thresholds in Car Following

A possible explanation for close following in fog is that it would allow drivers to control headway more precisely by reducing motion perception thresholds. The purpose of our experiments was to determine the motion discrimination thresholds for closing and receding under normal and foggy conditions. An experiment and a pilot study were conducted on a driving simulator in which subjects were presented with a car following situation. Subjects had to press a button as soon as they detected that the lead vehicle was closing or receding, and their choice response time was recorded. Several visibility conditions were tested corresponding to different contrasts between the lead vehicle outline and the background, ranging from clear weather conditions to foggy conditions in which the vehicle could only be seen by its rear lights. Initial headway and lead vehicle acceleration were also varied. As expected, response times were longest with small accelerations and long headways. There was also an effect of visibility conditions with longer response times when the contrast between the vehicle outline and the background was 5% or less. Moreover, the reduction of response time corresponding to a reduction of headway was greater in fog than in clear conditions, at least in the given range of distances. This suggests that driving closer in fog may have a perceptual-control benefit in terms of a reduction in response times that partially offsets the reduction in time-headway. Driving closer may also benefit lateral trajectory control because the lead vehicle is less likely to be lost in fog.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/9780874141580
• Corporate Authors:

  University of Iowa, Iowa City

  Public Policy Center
  227 South Quadrangle
  Iowa City, IA  United States  52242-1192
• Authors:
  • Caro, Stephane
  • Cavallo, Viola
  • Marendaz, Christian
  • Boer, Erwin
  • Vienne, Fabrice
• Conference:
  • Driving Assessment 2007: 4th International Driving Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design
  • Location: Stevenson Washington, United States
  • Date: 2007-7-9 to 2007-7-12
• Publication Date: 2007

Language

• English

Media Info

• Media Type: CD-ROM
• Features: Figures; References;
• Pagination: pp 446-451
• Monograph Title: Proceedings of the 4th International Driving Symposium on Human Factors in Driver Assessment, Training, and Vehicle Design, Stevenson, Washington, July 9-12, 2007

Subject/Index Terms

• TRT Terms: Acceleration (Mechanics); Car following; Driving simulators; Fog; Headways; Highway safety; Human subject testing; Motion perception; Reaction time; Traffic safety; Visibility; Weather
• Uncontrolled Terms: Thresholds
• Subject Areas: Highways; Safety and Human Factors; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 01055529
• Record Type: Publication
• ISBN: 9780874141580
• Files: TRIS
• Created Date: Aug 23 2007 1:01PM