WETSAFE – Effective detection of hazards and adapted behavior of (autonomous) vehicles in heavy rain events

Climate change is leading to an increase in extreme weather events, especially heavy rainfall events, which pose a high risk to road safety due to extreme amounts of precipitation in a short period of time. Heavy rainfall events usually occur in combination with thunderstorms. The challenge here is to make meaningful forecasts. A reliable forecast is not possible and long-term measures are difficult to plan. The risk for road users is further increased if vehicles are travelling at high speeds – as on the motorway – and this creates an acute risk of aquaplaning. The current surface drainage capacities on the motorway are often too low for heavy rainfall events and, depending on the amount of precipitation, road geometry and drainage capacity, critical water films form on the road surface, creating a high risk of aquaplaning. Secondary water ingress onto the carriageway from the surrounding area leads to an aggravation of the hazardous situation within a very short time, depending on the shape of the terrain and the amount of precipitation. Large volumes of water in a short space of time also lead to increased blockages in the drainage systems, which in turn impede the flow of water. The aim of the WETSAFE project is to develop a system that recognises potential hazards at an early stage in order to mitigate them and to derive and communicate measures for the traffic control of automated and conventional vehicles. The findings should not only be transferable to known danger spots, but also to the entire motorway network. To this end, a simulation model is being developed on the basis of a high-precision digital twin of the carriageway and its surroundings as well as predicted precipitation levels, which predicts the resulting water film (risk of aquaplaning) in heavy rain at the level of individual lanes.

The system is designed in such a way that it can be connected to existing traffic control technologies such as digital traffic control systems or C-ITS in order to inform road users or automated vehicles in good time so that driving behaviour can be adapted accordingly. The project will also derive specific recommendations for action.

In the event of a heavy rainfall event, the simulation model is used as a basis to provide situational information in real time.

As part of the project, the system is to be applied, demonstrated and evaluated as an example on a section of motorway with a known high risk. The realistic simulation of heavy rainfall events based on the digital twin will also make it possible to recognise potential bottlenecks in roadway drainage at an early stage and derive preventative infrastructure measures.