Visual search for traffic signs: The effects of clutter, luminance and aging

  • Published: University of Calgary, Human Factors, Volume 43, No.2, 2001
  • Authors: G. Ho, C.T. Scialfa, J.K. Caird and T. Graw
  • Date Added: 07 Feb 2013
  • Last Update: 20 Mar 2013
  • Format: pdf


To determine if observers could reliably estimate visual clutter in driving scenes and if these estimates of clutter would predict the efficiency of visual search for traffic signs by younger and older drivers.


Digitised images of driving schemes were presented to 14 older and 14 younger drivers covering both day and night-time scenarios and examples of high and low levels of clutter. Participants were asked to judge whether the images were low or high in visual clutter.

Key Findings:

  • Visual clutter can hinder sign acquisition and can confuse drivers through increasing the time required to process the information given. This is a particular problem for older drivers.

  • Scenes classified as high in clutter required longer latencies and more fixations to acquire specific sign, were associated with more errors, and had longer fixations durations than those low in clutter.

  • Older drivers were shown to be less accurate and slower than younger adults and executed more eye movements to acquire signs.


Signs, safety, RTIs, clutter, distraction


Fairly robust academic paper. Based on laboratory experiments.