Heuristic procedure for the optimization of speed consistency in the geometric design of single-lane roundabouts

This article presents a heuristic procedure for the optimization of speed consistency in the geometric design of single-lane roundabouts. The procedure is based on a real-code genetic algorithm that supports the optimization of roundabouts with any number of intersection legs and any angle between legs. The proposed methodology provides great flexibility to the design process, since it allows introducing the position of the centre of the roundabout, the inscribed circle diameter, the central island diameter, and the splitter island length as problem decision variables. The objective function may be formulated using any functional form, without the restrictions that are inherent in linear programming techniques. This flexibility renders the model highly suitable for solving the design problems that are often encountered in professional practice.