Solving the multi-airport Ground Holding Problem

The increasing demand for air traffic in the last years has led to a heavier use of airports and airways, while their capacities have not grown accordingly. The main drawback of this phenomenon is a situation of congestion in air traffic networks that produces departure delays and queues before landing, causes large losses to air companies and affects air traffic safety. A way of reducing congestion is to adopt a Ground Holding policy, i.e., to hold on the ground a limited number of flights before departure in order to avoid as much as possible airborne delay. The Ground Holding Problem (GHP) is that of determining a way of distributing delays to the flights in such a way as to minimize the overall cost of the delays (both on the ground and in the air). The importance of Ground Holding policies is well recognized and optimization models have been proposed; unfortunately, it is very difficult to have real, or "even realistic", GHP instances to evaluate the quality of one procedure over the others. Given this lack of GHP instances, in this paper we introduce 32 new test cases, up to 5000 flights on a network of 10 airports, in which congestion is caused by insufficient capacity in arrival airports. These instances (made accessible via ftp) are solved to computationally compare a new heuristic algorithm with both a previous heuristic and an exact algorithm. The new algorithm we propose is based on "priority rules", where the flight priority is computed as a cost function.