Improved driver comprehension of traffic management signing

  • Published: Institute for Transport Studies, 2008
  • Authors: S. Jamson
  • Date Added: 04 Feb 2013
  • Last Update: 20 Mar 2013
  • Format: pdf


To identify which roadwork scenarios have the most severe impications for both driver and roadworker safety; and to identify the types of signage in these scenarios that can cause confusion or anxiety.


A literature review was carried out.A laboratory based stimuli (tachistoscope) trial was carried out on 40 subjects.Driver focus groups were consulted.Driving simulator experiments were carried out on 34 subjects, incorporating behavioural, emotional and physiological measures.

Key Findings:

  • Drivers showed good comprehension of signs relating to lane drops. Focus groups established a range of behaviour from early to last minute merging, with each group believing that the other was behaving erroneously. This behaviour was largely played out in the driving simulator. Insertion of a new ‘merge in turn’ sign saw drivers change lanes earlier, although the difference was not statistically significant.

  • Drivers showed good comprehension of signs relating to narrow lanes. Although drivers exhibited anxiety related to passing HGVs, they typically appreciated that keeping lanes open maintained throughput.

  • Drivers showed some confusion relating to contraflow signs, however comprehension improved when confirmatory information was added (e.g. ‘use hard shoulder’). Additional confirmatory information on signs in the simulator trial did not influence timing of the lane change manoeuvre. Contraflows are associated with the emotion ‘cognition’, indicating a high driver workload.

  • Focus groups reported significant frustration with roadworks with no one apparently working. Drivers reported lost confidence in advanced signing and simulator trials revealed more aggressive driving and shorter headways having experienced ‘ghost’ road works.


Signs, comprehension, simulator trials


A credible recent study on driver understanding and emotional response to roadworks.