Judgements of approach speed for motorcycles across different lighting levels and the effect of an improved tri-headlight configuration

  • Published: Accident Analysis and Prevention 48 (2012) 341-345
  • Authors: Gould, D.R. Poulter, S. Helman, J.P. Wann
  • Date Added: 01 Feb 2017
  • Last Update: 01 Feb 2017
  • Format: html


To conduct a study examining how accurately individuals are able to judge the speed of motorcycles and cars across a number of different ambient light level conditions.


A simulator study of 14 participants recording perceived vehicle speed in different lighting conditions.

Key Findings

  • The accuracy of judgement remained constant for cars across all lighting levels.

  • Participant estimations of motorcycles with a solo headlight were significantly less accurate as lighting levels degraded.

  • The addition of a tri-headlight formation considerably reduced the degradation in speed judgements under lower light conditions. However, judgements were still poorer than the car.

  • Whilst this is less than optimal, the introduction of the tri-headlight formation could reduce the likelihood of right of way violation collisions occurring.

  • It was also suggested that media campaigns aiming to raise driver awareness could also aim to increase knowledge about the potential for inaccurate judgements of vehicle speeds, particularly for motorcyclists.


Perception, vision, looming, motorcycle, conspicuity


Systematic review.