The parking warden tour problem

In this work we introduce the parking warden tour problem (PWTP), a new arc routing problem arising in irregular parking detection to model the maximization of the fines collected by a team of parking wardens. The peculiarity of the PWTP is that the arc revenue depends on the time elapsed from the previous inspection of a warden, since the revenue on a road link slumps to zero if a warden has just visited the link. For this new arc routing problem and a variant of it, we propose two mixed integer linear program formulations, a simple but effective matheuristic based on them and a bounding procedure. All the solution approaches have been tested and compared on both real instances generated on a road network area of Milano, through a survey and on real-like random instances.