Field testing anti-speeding messages

Abstract

PurposeDetermine whether anti-speeding messages displayed on roadside variable message signage (VMS) influence drivers’ speed choice selections. MethodSpeed detection tubes were installed across a single carriageway 60 km/h limit road section at positions prior to, immediately after, and at a longer distance from VMS display of anti-speeding messages during study Week2. Bi-directional vehicle speed data were collected continuously during the week prior to VMS installation (Week1), throughout the week that the anti-speeding messages were displayed (Week2), and a post-display week (Week3). ResultsOf six separately measured locations, Week2 southbound mean speeds (facing signage) and percent of drivers/riders exceeding the signed speed limit were consistently below those recorded during Week1 for all time periods. Aggregated Week3 (post-VMS) southbound data for all time periods, showed consistent patterns for mean speed and percent of drivers exceeding the signed speed limit, being higher than in Week2 (VMS displayed) but lower than during Week1 (pre-VMS). DiscussionCompared with Week1, messages influenced aggregate driver speed selection during Week2, with a residual positive effect (slower speeds) in Week3. While all three messages had positive effects, differences occurred in relative effectiveness between daytime (school and non-school hours) and night-time periods. Separately disaggregated data revealed differential effects for the three messages. ConclusionsFindings demonstrated the value of implementing theoretically informed message content and provided evidence for the impact that roadside road safety messaging can have on driver speed selection.