Mobility Index-Based Navigation for Mandatory Re-Routing Scenarios

Roadway navigation systems have become increasingly popular, providing efficient routing through a roadway network. In most cases, routes are selected by minimizing some cost function, such as time or distance. However, a shortest-duration or shortest-distance route may not always work well due to unexpected roadway infrastructure conditions (e.g. unscheduled road shutdown) or major traffic problems, in which drivers will need to change routes on the fly. We refer to this as mandatory re-routing. There are several possible scenarios when mandatory re-routing is necessary, such as: 1) a major incident (i.e. accident) occurs, shutting down the roadway; 2) unscheduled emergency maintenance of the infrastructure; or 3) severe weather conditions. In many metropolitan roadway networks, traffic conditions are often very unpredictable. When roadways quickly become severely congested, drivers normally want to change their routes because the pre-defined route may no longer be optimal, i.e. the shortest-duration route may not guarantee minimal travel time and shortest-distance route may result in intolerable travel time. Re-routing capability is useful, but often real-time traffic information is delayed or non-existent. For these scenarios, it may be desirable to take a pre-defined route that gives the driver the highest degree of freedom (i.e. the path with the most routing choices) while traveling. In this paper, we describe a new routing methodology that is based on maximizing the routing choices while driving from a known location to a desired destination.