TRAFFIC CALMING AT MOBILE ROADWORK ZONES: USE OF VEHICLE-MOUNTED RADAR TO EVALUATE THE EFFECT OF VARIABLE MESSAGE SIGNS

摘要

Some of the worst accidents at roadwork zones in Sweden involve caravans of roadmarking vehicles. High traffic speeds past roadworks is recognised as a frequent causalfactor. This study was aimed at evaluating the traffic calming effect of a set of VariableMessage Signs (VMS), mounted on a slow-moving caravan of road marking vehicles. TheVMS displayed the maximum recommended speed throughout the zone. The results wereevaluated by means of new small portable radar equipment that surveyed the speed ofvehicles both passing and meeting the caravan.The case results showed that without activating the VMS, both the average and topspeeds were very high, thereby entailing an unacceptable risk. However, when the VMSwas activated, the average speed was reduced by 22 km/h on wide roads. Similarly, themean speed of the ten fastest vehicles was reduced by 16 km/h. Finally, the percentage ofvehicles driving at extremely high/hazardous speeds (> 70 km/h) dropped from 62% to12%, which is a relative reduction of 81%. As a result, Swedish legislation is beingreviewed with the intention to legalise the use of this type of VMS on moving road workvehicles.