  We propose in this paper a decentralized traffic signal control policy for
urban road networks. Our policy is an adaptation of a so-called BackPressure
scheme which has been widely recognized in data network as an optimal
throughput control policy. We have formally proved that our proposed
BackPressure scheme, with fixed cycle time and cyclic phases, stabilizes the
network for any feasible traffic demands. Simulation has been conducted to
compare our BackPressure policy against other existing distributed control
policies in various traffic and network scenarios. Numerical results suggest
that the proposed policy can surpass other policies both in terms of network
throughput and congestion.
