OPTIMAL INTERSECTION OPERATION WITH MEDIAN U-TURN: A LANE-BASED APPROACH

摘要

The median u-turn intersection is one potential method of relieving traffic congestion atintersections. According to the difference of the prohibited traffic movement, the median u-turnintersection concept can be extended into six different types. Although much is known about thetechnology of the median u-turn, efforts have mainly focused on its geometric design, safetyanalysis, and evaluation. In this paper, a lane-based optimization model is proposed for theintegrated design of median u-turn intersection types, lane markings, the distance between themedian crossovers and the main intersection, and the signal timings. The capacity maximizationproblem is considered, and a set of constraints is determined that ensure the feasibility and safetyof the optimization results. The optimization is formulated as a multi-objective mixed-integernon-linear programming problem. This is solved by transforming to a series of mixed-integerlinear programming models. The latter can be solved by the standard branch-and-boundtechnique. The results of extensive numerical analysis and a case study have shown theeffectiveness of the proposed method, as well as the promising property of assistingtransportation professionals in the proper selection of u-turn types and designing intersectionswith median u-turns.