Modeling the effects of turn delay uncertainties on route choice behavior in signalized road networks

Traffic flow fluctuation and traffic signal interruption result in turn delay variations at signalized intersections. Such variations can significantly contribute to road users' travel time uncertainties and affect their route choices in congested urban areas. A reliability-based stochastic user equilibrium (RSUE) model is proposed to investigate the effects of turn delay uncertainties on the route choice problem. In the proposed model, link travel times and turn delays are considered as correlated random variables with covariance relationships. Differences in these variables are mainly due to uncertainties at signalized intersections and day-to-day fluctuations in demand. Given these uncertainties, the concept of effective travel time is adopted to model the route choice behaviors of road users. The RSUE model also considers the perception errors of road users on effective travel times. A path-based solution algorithm is adapted to solve the RSUE problem. Finally, a numerical example illustrates the application of the proposed model and solution algorithm. Sensitivity tests are used to demonstrate the potential use of the proposed model to assess the accident risks at signalized intersections with heavy turning flows.