Preliminary highway design with genetic algorithms and geographic information systems

A method that integrates geographic information systems (GIS) with genetic algorithms (GAs) for optimizing horizontal highway alignments between two g iven end points is presented in this article. The proposed approach can be used to optimize alignments in highly irregular geographic spaces. The resu lting alignments are smooth and satisfy, minimum-radius constraints, as req uired by highway design standards. The objective function in the proposed m odel considers land-acquisition cost, environmental impacts such as wetland s and flood plains, length-dependent costs (which are proportional to the a lignment length), and user costs. A numerical example based on a real map i s employed to demonstrate application of the proposed model to the prelimin ary design of horizontal alignments.