Dynamic framework for weight optimization based urban road network operational state evaluation

Targeting the needs for dynamic evaluation of the road network traffic operational state, a dynamic framework for urban road network operational state evaluation is proposed based on heuristics weight optimization. In this framework, first, seven indexes are selected for intersections and sections, including saturation, delay, queue length, and equilibrium for intersections, and travel time, number of stops, and travel time dispersion for sections. Second, based on the seven indexes, a simple weighted average method is applied to evaluate the road network state following the intersection-section-network structure. Third, and most importantly, an optimization model is proposed and solved using particle swarm optimization algorithm to find dynamically the optimal weights with respect to expert evaluation during the optimization time interval. Finally, the optimized weights are then applied to evaluate the road network state for application time interval. The proposed framework is validated using VISSIM simulation for two road networks selected from Lianyungang City. Results show that the proposed framework can dynamically fine-tune the weights so that the road network operational state can be evaluated dynamically. Future studies are recommended to incorporate more indexes and apply the framework in real world applications.