A Semi-Cooperative Routing Algorithm to Reduce City Congestion 2019-01-0497
One of the ways to reduce city congestion is to balance the traffic flow on the road network and maximally utilize all road capacities. Normally, the traffic on the roads are somehow “self-balanced”. However, theoretical studies show that this natural self-balancing cannot achieve the optimal total travel time results, as every driver is selfish, not cooperative. There are examples showing that, if the drivers are not competitive but cooperative, the road network usage efficiency and the traffic conditions can be improved. This motivates the idea of designing a cooperative routing algorithm to benefit most vehicles on the road.
This paper presents a semi-cooperative routing algorithm for large transportation network with predictive traffic density information. The goal is to integrate a cooperative scheme into the individual routing and achieve short traveling time not only for the traveler itself, but also for all vehicles in the road network. The most important concept of this algorithm is that the route is generated with the awareness of the total travel time added to all other vehicles on the road due to increased congestion. Based on the macroscopic fundamental diagram of different road segments in the road network, this impact of routing one more vehicle to the road segment can be quantified, and its value can be considered as a measure of individual vehicle’s contribution to congestion, and used as part of the cost in the shortest-path algorithm. A trade-off is made between being extremely selfish and extremely cooperative.
This routing algorithm can be used to create a route for a specific user. It also can be used to scan the road network in a small area to provide suggestions to the transportation governance authority to dynamically close and open different roads, or change roadside displays in real time based on traffic conditions.