Optimal Deployment of Cordon Sanitaire with Available Testing Capacity

During the COVID-19 pandemic, authorities in many places have implemented various countermeasures, including setting up a cordon sanitaire to restrict population movement. This paper proposes a bi-level programming model to deploy a limited number of parallel checkpoints at each entry link around the cordon sanitaire to achieve a minimum total waiting time for all travelers. At the lower level, it is a transportation network equilibrium with queuing for a fixed travel demand and given road network. The feedback process between trip distribution and trip assignment results in the predicted waiting time and traffic flow for each entry link. For the lower-level model, the method of successive averages is used to achieve a network equilibrium with queuing for any given allocation decision from the upper level, and the reduced gradient algorithm is used for traffic assignment with queuing. At the upper level, it is a queuing network optimization model. The objective is the minimization of the system’s total waiting time, which can be derived from the predicted traffic flow and queuing delay time at each entry link from the lower-level model. Since it is a nonlinear integer programming problem that is hard to solve, a genetic algorithm with elite strategy is designed. An experimental study using the Nguyen-Dupuis road network shows that the proposed methods effectively find a good heuristic optimal solution. Together with the findings from two additional sensitivity tests, the proposed methods are beneficial for policymakers to determine the optimal deployment of cordon sanitaire given limited resources.

A literature review on park-and-rides

American cities have been implementing park-and-rides (PNRs) since the 1930s; however, there has been a recent resurgence of literature examining this type of transit station. This paper aims to provide a comprehensive review of the current literature on PNRs and directions for future research. PNR studies published in the last ten years were reviewed and text mining was applied to extract key themes. Six themes were identified. The two most common areas of research were network equilibrium and optimization (12 of 37 studies) and demand models (8 of 37 studies). This was followed by guidelines and best practices as well as comparative studies (6 of 37 studies each). Parking utilization had the fewest number of recent studies (3 of 37 studies). This review revealed that the majority of PNR studies were conducted in geographic areas with extensive transit services, most studies have focused on rail-based PNRs, and the most widely used method was multinomial logit. Some areas for future research include studying remote PNRs, examining bus-based PNRs, and assessing the impact of emerging modes on PNR utilization. This systematic review could assist planners and transit agencies in further improving sustainable PNR networks in their cities.