Optimal conversion of an evacuation network to signalized and uninterrupted flow 1 intersections 2 3

2014 TRB

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.