Evidence that implementation intentions reduce drivers’ speeding behaviour: Testing a new intervention to change driver behaviour

  • Published: Accident Analysis & Prevention Volume 74, January 2015
  • Authors: S.E. Brewster, M.A. Elliott, S.W. Kelly
  • Date Added: 10 Feb 2016
  • Last Update: 10 Feb 2016
  • Format: html


To test the effects of implementation intentions in the context of drivers’ speeding behaviour.


A randomised controlled trial was used where speeding behaviour, goal intentions and theoretically derived motivational pre-cursors of goal intentions were measured at both baseline and at one month follow up, using self-report questionnaires.

Immediately after baseline, the experimental group (N=117) specified implementation intentions using a volitional help sheet, which required the participants to link critical situations in which they were tempted to speed with goal-directed responses to resist the temptation. The control group (N=126) instead received general information about the risks of speeding.

Key Findings:

  • The experimental group reported exceeding the speed limit significantly less often at follow up than did the control group.

  • This effect was specific to ‘inclined abstainers’ (participants who reported speeding more than they intended to at baseline and were therefore motivated to reduce their speeding) and could not be attributed to any changes in goal intentions to speed or any other measured motivational construct.

  • The findings imply that implementation intentions are effective at reducing speeding and that they do so by weakening the effect of habit, thereby helping drivers to behave in accordance with their existing goal intentions.

  • The volitional help sheet designed in the study was easy to administer and cost effective at achieving the aim.

  • Whilst implementation intentions were found to reduce speeding for inclined abstainers only, it should be noted that this group comprised 45.3 per cent of the overall sample.


There is the potential to use the techniques employed in this study to bring about widespread reductions in speeding.