Errors in judging the approach rate of motorcycles in nighttime conditions and the effect of an improved lighting configuration

  • Published: Accident Analysis and Prevention, 45 (2012) 432-437
  • Authors: Gould M, Poulter D R, Helman S and Wann J P
  • Date Added: 25 Jan 2014
  • Last Update: 25 Jan 2014
  • Format: html

Objectives:

To explore drivers’ abilities to make judgments of motorcycles and car approach speeds in night time driving conditions, when only the headlights are visible, as well as the effectiveness of a tri-headlight configuration on the accuracy of motorcycle speed judgments.

Methodology:

A sample of 13 participants was subjected to visual stimuli. The stimuli were presented on a 34 cm × 27 cm Cathode Ray Tube monitor display (1024 × 768 pixels). In this instance, participants were asked to indicate which of two visual stimuli presented sequentially was travelling at the fastest speed. The appropriate car stimulus was used as a reference vehicle in all trials, travelling towards the observation point at a fixed speed of 30 mph (13.4 m/s).

Key Findings:

  • Individuals were significantly more accurate at judging the speed of two car headlights compared with the standard solo headlight motorcycle. However, the inclusion of a tri-headlight formation on a standard motorcycle frame significantly improved these judgments.

  • A further investigation demonstrated that tri-headlight configurations with separation between headlights on the horizontal and vertical axes are most effective for yielding accurate speed judgments.

Keywords:

Perception, vision, looming, tau, motorcycle, conspicuity

Comments:

As noted by the authors, “The extent to which observers struggle to accurately judge motorcycle speed based on a solo headlight in night time conditions is rather alarming.”

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