General Road Networks Research Articles

Reserve capacity of a signal-controlled road network

The concept of reserve capacity has been used extensively for performance measure and timing design of individual signal-controlled intersections. In this paper, we extend this concept to a general signalcontrolled road network under time-stationary conditions. The whole capacity of a road network is controled by intersections whose capacity depends on traffic signal settings. We first define and formulate the reserve capacity of a whole signal-controlled road network, and then show how a bi-level programming method can be used to determine signal setting for maximization of the network reserve capacity. A numerical example is presented to illustrate the concept and the calculation procedure.

A link-based variational inequality model for dynamic departure time/route choice

The dynamic user-optimal (DUO) departure time and route choice problem is to determine travelers' best departure times and route choices at each instant of time. In a previous paper, we presented a route-based two-level optimal control model for the DUO departure time/route choice problem. However, this model is not appropriate for large scale transportation networks because some degree of route enumeration is necessary to solve the model. In this paper, we present a link-based variational in equality (VI) formulation for the DUO departure time/route choice problem so that route enumeration can be avoided in both the formulation and the solution procedure. The model extends our previous VI model for the DUO route choice problem to the case where both departure time and route over a general road network must be chosen simultaneously. By proving the necessity and sufficiency of this VI, we establish the equivalence of the VI formulation and the link-based DUO departure time/route choice conditions.