Some of the worst accidents at roadwork zones in Sweden involve convoys of road marking vehicles. High traffic speeds past roadworks is recognised as a frequent causal factor. This study was aimed at evaluating the traffic calming effect of a set of Variable Message Signs (VMS), mounted on a slow-moving convoy of road marking vehicles. The VMS displayed the maximum recommended speed throughout the zone. The results were evaluated by means of new small portable radar equipment that surveyed the speed of vehicles both passing and meeting the convoy. The case results showed that without activating the VMS, both the average and top speeds were very high, thereby entailing an unacceptable risk. However, when the VMS was activated, theaverage speed was reduced by 22 km/h on wide roads. Similarly, the mean speed of the ten fastest vehicles was reduced by 16 km/h. Finally, the percentage of vehicles driving at extremely high/hazardous speeds (> 70 km/h) dropped from 62% to 12%, which is a relative reduction of 81%. As a result, Swedish legislation is being reviewed with the intention to legalise theuse of this type of VMS on moving road work vehicles. For the covering abstract see ITRD E139491.
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