Optimization Model for Allocating Resources for Highway Safety Improvement at Urban Intersections

Abstract

The authors present a procedure for allocating resources for implementing safety improvement alternatives at urban intersections over a multiyear planning horizon. The procedure, on the basis of optimization techniques, attempts to maximize benefits measured in dollars saved by reducing crashes of different severity categories subject to budgetary and other constraints. It is presented in two parts: (1) a base case including the objective function and a set of mandatory constraints; and (2) additional policy constraints/special features that can be separately incorporated to the base case. Demonstration of the procedure is presented on intersections in the Detroit metropolitan region, in which economic losses resulting from traffic crashes at intersections are estimated to exceed $4 billion annually. The proposed model can allocate resources for safety improvement alternatives over a planning horizon, given a number of independent locations and a number of mutually exclusive alternatives at each location. The policy constraints provide the analyst the flexibility of adding equity, urgency, and other features to the base case. An integer programming technique is applied to solve the demonstration problem.