Saving a path minimizing egress time of a dynamic contraflow: a bi-objective programming approach

Reversing the direction of traffic flow in necessary road segments is an important strategy to optimize the flow, especially, in an emergency evacuation. The configuration may, however, block the paths toward the source. Sometimes, it may be necessary to save a path for some facility movements from a specific node towards the source. We consider such a problem as a biobjective optimization problem that minimizes the length of the saved path and the egress time of the given amount of flow. An algorithm based on the e-constraint method is proposed to find the non-dominated solutions and its computational performance has been tested on a road network of Kathmandu city and randomly generated networks.