Author: Yue Liu, Daizong Liu, Jie Yu , Xin Li, Peng Li
Due to the advantage over signals in expanding network capacity, the strategy of using uninterrupted-flow (or crossing-elimination) intersections has been viewed as one of the most effective means for managing evacuation traffic. However, implementing such a strategy may demand a large amount of manpower and resources, and often need some evacuees to take additional detours. To optimize the selection and distribution of signalized and uninterrupted flow intersections in an evacuation network, this article presents a mathematical model with equilibrium constraints to yield the maximum operational efficiency under the available budget. The proposed model, incorporating a parametric variational inequality (VI) toformulate the user equilibrium (UE) behavior of evacuees in route choice, is capable of providing effective solutions to the following critical questions that have long challenged transportation professionals for strategic planning of an emergency orspecial event: 1) how many intersections should be implemented with the signals and interrupted flow controls; 2) what would be the optimal spatial distribution for those intersections in the target network; and 3) how to best plan turning restriction, channelization, and signal timings at those intersections? In view of the large number of variables and constraints for the proposed model, this study has developed an efficient heuristic approach embedded with a diagonalization algorithm to yield the meta-optimal solutions. An extensive numerical analysis with a sub-network in Washington DC is also performed to demonstrate the applicability and effectiveness of the proposed model.