Vehicle Activated Signs: An emerging treatment at high risk rural intersections

Vehicle Activated Signs (VAS) aim to improve safety by warning drivers to exercise caution and/or reduce their travel speeds at particular locations. This study examined the effect of VAS on the speeds of drivers approaching selected rural intersections in south-western Victoria. Six VAS were installed on rural undivided arterial approaches to T-intersections with limited sight distance from a side road. The VAS were activated by a movement sensor that detected the presence of vehicles on the side road. The speeds of main road drivers were recorded using pneumatic tubes. Arterial road speeds recorded at treatment sites were compared with speeds at selected comparison sites where standard static signs were present. Analysis of variance was used to compare mean speeds before and after treatment installation, controlling for any changes across comparison sites. At four sites, the treatment delivered statistically significant speed reductions of between 0.8 and 6.9 km/h. Increases in mean speeds of between 0.5 and 3.4 km/h were observed at the remaining two sites. The 85th percentile speeds followed mean speed trends. VAS may also deliver an increase in driver alertness. Other implications, including estimated crash reduction factors for this type of VAS application, are discussed further in this paper.