Optimal traffic counting locations for origin–destination matrix estimation

There has been substantial interest in development and application of methodology for estimating origin–destination (O–D) trip matrices from traffic counts. Generally, the quality of an estimated O–D matrix depends much on the reliability of the input data, and the number and locations of traffic counting points in the road network. The former has been investigated extensively, while the latter has received very limited attention. This paper addresses the problem of how to determine the optimal number and locations of traffic counting points in a road network for a given prior O–D distribution pattern. Four location rules: O–D covering rule, maximal flow fraction rule, maximal flow-intercepting rule and link independence rule are proposed, and integer linear programming models and heuristic algorithms are developed to determine the counting links satisfying these rules. The models and algorithms are illustrated with numerical examples.