A token-based admission control and request scheduling in lane reservation systems

In many parts of the world, the ever-expanding traffic congestion problem has become a major source of wasted fuel, economic burden, and environmental pollution. Alleviating traffic congestion is not only a matter of expanding the transportation capacity, such as adding more lanes or building new roads, but also the problem of providing good traffic management and polices. Recently, the concept of road reservation systems has been widely discussed. With this system, in order to use the lanes and roads controlled by the transportation operators, drivers make reservations in advance. The goal of the system is to provide certain quality of services to the drivers, e.g., guaranteed end to end travel delay. In this work, we focus on the admission control and request scheduling for a reservation system. Specifically, we consider a high-priority lane reservation scenario, in which the system has to determine which vehicles could be allowed to enter the high-priority lane, so that the traffic workload does not exceed the lane capacity. We present a token-based admission control policy that implements the reservation scheme. We have also designed an on-line scheduling algorithm that selects which reservation requests can be allowed based on the admission control policy. Using a simulation model to evaluate the system performance in a variety of scenarios, we show that the proposed algorithm can achieve efficient utilization of the high priority lane.