Reversed Traffic Assignment for Staggered Shifts with User Equilibrium

摘要

Staggered shifts are a common traffic demand management, aiming to relieve traffic congestion in peak hour. They move part of traffic demand to a later period, and lead to the original equilibrium state of the system disappearing. Staggered commuters will adjust their home departure time with consideration of renewed work start time and renewed perception or experience of road traffic volume, and some commuters with a relatively late work start time may encounter a more crowded network so they will choose an earlier home departure time, with the final consequence that the system reaches a new equilibrium state. To study the effect of a giving staggered shifts policy on system and commuting behavior, this paper firstly introduces reversed traffic assignment (RTA), then proofs the dual relationship between RTA and forward traffic assignment with user equilibrium, and finally proposes a RTA based model to obtain the transformation of time-varying system state and the commuters' departure time with consideration of before and after staggered shifts implementation. A numerical test illustrates the model and shows the model can derive the above results with acceptable accuracy. In addition, this study can provide traffic administrations with method to evaluate a giving staggered shifts policy for better management.