Analysis of Traffic Safety at Road Works
W Weijermars, SWOV, NL; H Spittje, CROW, NL
On the basis of a literature review, a study on recent crashes and charges and visits to work zones insight is obtained into traffic safety at work zones. The main lesson learnt is that special attention should be paid to bicyclists and pedestrians.
Road works create a risk, both to road workers and drivers. To be able to take effective measures to prevent crashes, insight into the causes and circumstances of these crashes is crucial. The SWOV conducted research to enhance this insight, founded by CROW. On the basis of a literature review and a study on recent crashes, information is gathered about the amount, location, time and types of crashes. Furthermore, an analysis of charges of 58 severe crashes provided more insight into the causes of crashes at work zones. Finally, 50 work-zones were visited to obtain more insight into (1) the extent to which the Dutch guidelines for safe road works are applied and (2) work zone characteristics that cause potential unsafe situations.
From the study on recent crashes we found that in the Netherlands, 166 severe crashes occurred at road works in 2005. This accounts for about 2% of all severe crashes. Furthermore, this percentage has increased over the last two decades. Since reliable data on the amount of road works is lacking, the risk of a crash could not be calculated. Also the literature studied does not provide a clear conclusion on the risk of a crash at road works, although most studies found an increase in the risk. Highways show a relatively high percentage of crashes at road works and lorries are relatively often involved in crashes at road works. From the analysis of the charges it is found that on urban roads, the high percentage of crashes involving lorries can be explained by the involvement of road works vehicles that collide with pedestrians or bicyclists. The characteristics of other crashes at urban roads do not differ greatly from the characteristics of crashes under 'normal circumstances'. On rural roads and highways, relatively many head-tail crashes occur at road works. From the analysis of the charges we found that these crashes often occur at the tail of the traffic jam that is due to the road works. Also crashes with parked vehicles and objects lying on the road relatively often occur at road works on highways and rural roads. From the analysis of the charges we found that these are crashes with vehicles and material that are involved in the road works. From the analysis of the charges we also found that road works do not play a vital role in all crashes that occur at road works. Of the 58 crashes for which the charge was analysed, 20 would most probably also have happened in case there were no road works.
Almost none of the visited work-zones met all guidelines. However, often work zones show only small deviations from the guidelines, like the lacking of one sign in the alternative route. Furthermore, road closures in urban areas are in some cases inadequate and sometimes there is a lack of clarity about the way bicyclists and/or pedestrians should act. This can explain the crashes involving bicyclists or pedestrians and road works vehicles.
The conducted research enhances the insight into traffic safety at work zones. The main lesson learnt is that at work zones, special attention should be paid to bicyclists and pedestrians. The guidelines discuss measures that should be taken, but they are often not followed entirely. In case bicyclists are able to pass the road closure they will. Therefore, we advice to take other measures for bicyclists if possible. Furthermore, in case it is really necessary to close the road for bicyclists as well, it should be done in such a way that it is impossible for them to pass the road closure. Finally, it should be clear for all road users (also for bicyclists and pedestrians) what behaviour is expected from them.
Association for European Transport