The detection layout problem

The main traffic models, either for planning or operational purposes, use as major data input Origin-Destination (OD) trip matrices describing the patterns of traffic behavior across the network. OD matrices become in this way a critical requirement of Advanced Traffic Management or Information Systems supported by Dynamic Traffic Assignment models. However, as far as OD matrices are not directly observable, the current practice consist of adjusting an initial or seed matrix from link flow counts provided by an existing layout of traffic counting stations. The adequacy of the detection layout strongly determines the quality of the adjusted OD. Usual approaches to the Detection Layout problem assume that detectors are located at network links but some of the Information and Communication Technologies specially those based on the detection of the electronic signature of on board devices, as for example Bluetooth devices, allow the location of sensor at intersections. This paper proposes a reformulation of the link detection layout problem adapting the classical set covering approaches with side constraints and solving it efficiently by a tabu search metaheuristic. For the intersection layout covering problem a reformulation is proposed in terms of a node covering problem with side constraints that for practical purposes can be efficiently solved with standard professional solvers.