Rivers and streams, like transportation networks, are widely spread across the landscape providing many opportunities for intersections with roads. These crossings are points of potential vulnerability for transportation infrastructure. Road-stream crossings are a critical, and sometimes vulnerable, component of the transportation system. Flooding and erosion associated with severe storms can disrupt transportation networks and thus the ability to provide essential services. Crossing failures can be more than an inconvenience; they can threaten public safety and result in significant economic impacts.
Recent severe storms in the Northeastern USA has raised concerns about the vulnerability of road-stream crossings, and transportation networks in general, to flood damage. In 2011, tropical storm Irene resulted in widespread damage to roads and highways in VT, NY and MA, including the failure of over 1000 stream crossings in Vermont alone. With climate change models forecasting storms of increasing severity and a higher frequency of severe storms, state departments of transportation are beginning to take the issue more seriously.
Transportation vulnerability includes three factors: