  In this paper, we present a cyclically time-expanded network model for
simultaneous optimization of traffic assignment and traffic signal parameters,
in particular offsets, split times, and phase orders. Since travel times are of
great importance for developing realistic solutions for traffic assignment and
traffic signal coordination in urban road networks, we perform an extensive
analysis of the model. We show that a linear time-expanded model can reproduce
realistic travel times especially for use with traffic signals and we verify
this by simulation. Furthermore, we show how exact mathematical programming
techniques can be used for optimizing the control of traffic signals. We
provide computational results for real world instances and demonstrate the
capabilities of the cyclically time-expanded by simulation results obtained
with state-of-the-art traffic simulation tools.
