Veilig stoppen van wegverkeer bij beweegbare bruggen in beheer van Rijkswaterstaat : literatuurstudie met aanbevelingen voor de inrichting van het voorwaarschuwingssysteem.

Bringing traffic to a safe stop at movable bridges : literature review with recommendations for the design of the initial warning system. The Centre for Transport and Navigation (DVS) of the Directorate-General for Public Works and Water Management in the Netherlands is working at the design of new policy to further improve road user safety at movable bridges under its responsibility. One of the reasons for this new policy are several incidents which occurred at these types of bridges, one of them being the ‘Ketelbrug’ between the Dutch towns of Lelystad and Emmeloord. In recent years DVS organized several expert meetings to answer the question of how the road user can be brought to a safe stop at a bridge. The initial warning system for the ‘Ketelbrug’ has already been replaced by a new, temporary system. SWOV was asked to provide knowledge for the design of this initial warning system, and was specifically asked whether initial warnings at 900, 600, or 300 metres would be more effective and safer than an initial warning at 1500 metres (as was the case in the old situation). The literature used in this small-scale study provides general knowledge. This knowledge appears to be insufficient for a specific recommendation for the actual distance at which initial warning should commence. However, indications were found to be careful with initial warning at ‘very’ close distance from the bridge On the other hand, it is also important not place the initial warning at ‘too” large a distance from the bridge. This leaves the question of what exactly the optimal distance is. Furthermore, account must be taken of the variety of other aspects that may have a role in the safest possible design of the initial warning system. Examples are uniformity, homogeneity, credibility, understandability, communication of the reason why, communication in general, gradual activation of the initial warning system or switching on the entire system in one go, habituation, getting out of the habit, and confusion. Further research into behaviour and incidents in traffic in the proximity of movable bridges is recommended. This research can be carried out both in practice and in a simulator. This will provide more clarity about a safe design of the initial warning system.