Vehicles vulnerability to flood

Most of fatalities during floods are vehicle-related, thus it is crucial to understand the vulnerability of flooded vehicles to better manage flood risk and improve emergency plans. Based on existing flume experiments on the incipient motion of scale and prototype vehicles and on dimensionless parameters a new regression curve identifying the critical threshold of instability is drawn. The presented regression curve shows that with more data on extremes, i.e. highly supercritical and zero flow velocity conditions, the vulnerability of flooded vehicles is better explained by means of a dependence between critical relative submergence Sr and Fr-1. The vulnerability curve explains well the behavior of several car model and flow orientations, thus providing a valuable tool for flood risk mapping.