Multi-Objective Optimization of Intersection and Roadway Access Design

摘要

Managing the increasing traffic congestion and safety issues that occur ingrowing areas is one of the most pressing worldwide issues. Congestion and accidents often occur because of conflicting traffic maneuvers at roadway intersections where design and operation are comprised of a complex set of parameters, which include number of traffic lanes, number and length of turning lanes, spacing between access intersection points, and traffic control devices. Congestion and safety issues often are the result of inadequate design of the access and intersection points, which often are established in the early stages of adjacent roadway development when such inadequate designs are not noticeable or given much importance. Poor site intersection designs also can be attributed to developer and political pressure, especially where there is a lack of consistent design regulations, a lack of knowledge of design criteria, and the focus is only on one of several measures of effectiveness. Poor site design of driveway access and intersection points is a major cause of accidents and traffic congestion. The overall goal of this research is to develop an efficient methodology for designing optimal access intersections and incorporating multi-objective evaluation techniques to examine the trade-off between delay, risk, and cost. The process includes a rule-based expert system--heuristic rules based on published criteria in applicable manuals and research reports; the evaluation of three objective functions: average vehicle delay, intersection accident risk, and intersection construction costs; and intelligent processes to assess the objective functions and the remaining search space of valid alternatives and to what degree design parameters should be altered and reevaluated. To demonstrate this approach to improving design, several example case studies of actual roadway access points were tested and results have been shown.