Patrol Routing Expression, Execution, Evaluation, and Engagement

Abstract

Recommended patrol routes can be used by organizations such as police agencies, emergency medical responders, and taxi services whose agents patrol roadway segments at proper times to assist or deter their target events. The creation of optimal complementary patrol routes for multiple agents targeting temporal event hotspots and minimizing travel distance is an NP-hard combinatorial problem that belongs to a class of problems known as the vehicle routing problem with time windows (VRPTW). Traffic safety patrol routing problems share many characteristics of VRPTW problems but differ in ways that prevent the application of existing solutions. In our approach, nondeterministic patrol routing algorithms are used to specify the movements of simulated mobile agents on a roadway system. Nondeterminism is critical in the traffic safety patrol routing domain, as rigidity and predictability can negatively impact the effectiveness of law enforcement agents' efforts.This paper addresses the problem of expressing, executing, evaluating, and engaging patrol routing algorithms that target event hotspots on roadways. The patrol algorithms are first expressed using Turn, which is our extensible domain-specific language (DSL) created for this purpose. Algorithms specified using Turn syntax are then executed in a custom simulation environment. Utilizing predefined metrics, users evaluate the resulting patrol routes to ensure that the criteria of interest in a given patrol context are met. Acceptable patrol routes are then engaged by end users via a web-based geographic information system (GIS) portal. To demonstrate the applicability and efficacy of our approach, we present two illustrative case studies.