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Calamity routes: alternative routes by traffic disruption

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A serious road incident blocks the motorway, now what? Flanders developed a system of calamities routes, the so-called emergency routes, to ensure that drivers still reach their destination despite the severe traffic disruption. Those emergency routes must be well signposted to let traffic circulate smoothly. This study focuses on the calamity routes on the Cloverleaf in Lummen. When a motorway gets blocked, the traffic will be diverted via four alternative routes. Since the junction was redesigned recently, Roads and Traffic Limburg (Wegen en Verkeer Limburg) wants to test whether the routes are still clearly marked. Roads and Traffic Limburg appealed to IMOB for advice.

Phased message strategy
IMOB evaluated the effectiveness of a phased message strategy, that gives drivers information piece by piece. First, dynamic signs inform them about what has happened and about which exit they need to take to reach to their destination (e.g. accident E313  direction Antwerp + Liège, take Exit 27). When arriving at the exit, the drivers get informed about the letter from the alphabet they have to follow (e.g. for Antwerp – follow route F). The direction is indicated at the end of the exit, where the drivers turn onto a national road (e.g. Route F – to the left).

By carrying out a driving simulator study, we identify bottlenecks in the five existing scenarios. The test subjects drove on the motorway E314 coming from Genk/Aken or Brussel/ Leuven. Researchers gave them the instruction to follow a particular direction (e.g. You are on your way to Leuven). Researchers checked whether the drivers followed the right letter code. The images that are projected on the screens in front of the driving simulator, were recorded in advance. We linked the results with the looking behaviour of the test subjects. This study has shown that a phased message strategy seems to work, but IMOB formulated several recommendations to optimize those routes.

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