Stochastic cell transmission model for traffic network with demand and supply uncertainties

This article extends the stochastic cell transmission model (SCTM) to simulate traffic flows on networks with stochastic demand and supply. The SCTM divides a roadway segment into cells and accepts the means and variances of stochastic travel demand and supply functions as exogenous inputs, and produces the corresponding cell traffic densities over time. This article defines the rules of flow propagation for freeway corridors, traffic merges/diverges and signalised junctions based on a kind of link-node model. In the numerical studies, we simulate the proposed model with a hypothetical network. We apply the SCTM to estimate the queues and delays at signalised intersections. Compared with some well-known delay and queue estimation formulas, e.g. Webster, Beckmann, McNeil and Akcelik, the results show good consistency between the SCTM and these formulas. In addition, the SCTM describes the temporal behaviour of the queue and delay distributions at signalised junctions with stochastic supply functions and (non-stationary) arrivals.