An Analysis of Public Posting in Reducing Speeding Behavior on an Urban Highway

Using a reversal design, the percentage of drivers speeding on an urban highway was measured with a concealed radar unit (baseline condition). During the daily posting condition a highway sign was installed that provided feedback on the percentage of drivers not speeding the day before and the best record to date. This sign was then covered and reintroduced. The sign was effective in reducing speeding behavior, and the effects were most pronounced in reducing the speeds of the faster drivers. When daily and weekly postings were compared with the sign alone without numerical feedback, it was found that the weekly posting condition was as effective as the daily posting condition, but that the sign had no influence when numbers were not posted. The weekly posting procedure remained effective during a 6-mo follow-up. (21 ref)