APPROACH TO COMBINE RANKING AND OPTIMIZATION TECHNIQUES IN HIGHWAY PROJECT SELECTION

In pavement and bridge management systems, often two different techniques are employed for selecting rehabilitation and replacement projects. Prioritization or ranking techniques provide a list of projects ranked according to a given set of criteria. Optimization, on the other hand, gives a list of projects that satisfies a set of criteria including budget and other constraints over a certain period. The two may produce two different sets of results because of the difference in approaches. To have consistency in decision making, it is desirable to connect the two project selection models so that their results are comparable. The ranking and optimization models would then have a direct correspondence and the results could be compared and analyzed on the basis of common criteria. An approach combining ranking and optimization techniques is presented. The approach is illustrated by using an example of bridge management for Indiana. First, the ranking and optimization models are briefly introduced, and the concepts of the new approach based on the existing models are presented and explained. A numerical example is given, and the results from the new approach and the existing ranking model are compared and discussed through the example.