## 3 Framework  
To capture the relationship between road transport system and flood, integration of flood and traffic during the flood and after the failure of assets is carried out, flood maps were obtained using a time-series of water levels, and their outcomes were translated into time traffic model inputs. The rationale is that severity (depth and extent) and propagation of flood over time determine the condition on the road [6]. During a flood, a consistent and homogenous approach is developed to incorporate the temporal change of both flooding and network capacity to enable comprehensive and dynamic communication between the flood and the traffic models. Depending on the depth of flood, certain roads may be attributed to delayed traffic while others may already be considered closed to traffic. According to previous research on flooded vehicle stability thresholds, a criterion for distinguishing shallow from deep water flows was defined [6]. In order to guarantee consistency for all simulated vehicles in the road network, a value of 0.3 m water depth has been considered a criterion for street closures, whereas for values lower than 0.3 m a reduction of speed to 20 km/h was considered for that link [6]. When a street is blocked from traffic, vehicles that were previously going through it are rerouted just before the link closure by taking the shortest path from their current place to their destinations. In this rerouting process, it is assumed that drivers are not aware of the flooded part of their route until they approach the closed link and then they choose a new route to their destination considering the shortest path.  
A framework that translates spatially fluctuating flood information into a traffic model output could ensure the interoperability of the previously stated activities. This framework may be applicable for both static and dynamic ways of modelling. Dynamic integration of flood and traffic models applies flood maps at different time steps of an event. To do so, in the traffic model, temporal flood propagation is directly translated into speed reductions or road closures. On the other hand, for all flooded roads, the static integration employs a single flood map within a whole day period. This method could be sufficient and practical to simulate the disruption effects because of flooding in the days following the event itself, but all the flooded links are closed to the traffic for activities such as dredging or repairing, while the transport network adapts to the new situation. This paper simulates both dynamic and static integrations of a flood event, respectively during the day of the flood and on one following day, when flood has subsided but its disruption effects on the transport network remain. Figure 1 presents the different steps of the integrated framework.  
In this research, a mesoscopic simulation has been employed for the flood impacts assessment. With a mesoscopic modelling technique, the trips must be computed for each travel mode in the network. Mesoscopic simulation computes vehicle movements with queues and may run up to 100 times faster than a microscopic model [8]. Furthermore, by using a coarser model, it is more tolerant of network modelling errors than microscopic simulation. In this perspective, mesoscopic traffic models can provide a complete picture of congestion as well as an intermodal explanation of different types of vehicles.  
After running the traffic model with the flood information, its impacts on the road network can be achieved by comparing the traffic model results under flood and normal conditions. The effects on the traffic system are expressed as additional travel time and additional travel distance. Using this method, the effects of flood risk management and traffic improvement systems can be evaluated.