Optimal Design of Midblock Crosswalk to Achieve Trade-Off between Vehicles and Pedestrians

Midblock crosswalks are installed mainly at locations with heavy pedestrian traffic to increase the accessibility of points along the streets to pedestrians. However, midblock crosswalks may cause additional delays for vehicles. This paper presents an integrated design method for midblock crosswalks that balances the trade-off between the efficiency of vehicle operation and pedestrian crossing by making full use of the vehicular red time at the downstream intersection. The method combines location selection and signal timing in a unified optimization model that is formulated as a multiobjective linear programming problem. The Pareto frontier of the proposed model is obtained by iterating all possible combinations of the weights of the two objectives. For each combination of weights, the optimization problem becomes a single-objective mixed-integer linear programming problem that can be solved with the standard branch-and-bound technique. The results of extensive numerical analyses and case studies demonstrate the effectiveness of the proposed model and indicate its promising application in providing additional crosswalks for pedestrians while only slightly impacting vehicular operations. (C) 2016 American Society of Civil Engineers.