Measuring the impact of digital information displays on speed: a driving simulator study

Abstract

Speeding is a major problem in today's society and is estimated to contribute to about 30 percent of all fatal crashes. The primary objective of this study was to examine the impact of digital information displays on speeding behavior at 70km/h-to-50km/h transition zones. Two real world locations with a high percentage of speeding violations are rebuilt as realistically as possible in a driving simulator. Sixty-six participants completed an 18.9 km trip within a randomized between (location: A,B)- within (condition: no display or one of three display messages: smiley, "You are speeding!/ Thank you" or "Speed control") subjects design. The first two messages are social approval/disapproval messages, while the "Speed control" message confronts drivers with the (financial) risk of receiving a fine (i.e., a message more explicitly related to enforcement). Results show a significant speed reduction effect of the three digital messages compared to the control condition from 50m before the digital display until 100m after the digital display. The largest mean deceleration was located between 50m and 25m before the digital display. The speed reduction effect of the "You are speeding/Thank you" and "Speed control" messages lasted until 175m after the digital display. Overall, the "Speed control" condition was found to be most effective (in terms of effect size as well as in terms of distance) in reducing speed. Finally, 500 meters after the devices no significant speed reduction was observed anymore. These results imply that a message more explicitly related to enforcement is more effective in reducing speed in speed transition zones compared to messages that socially disapprove speeding.