A new delay parameter for variable traffic flows at signalized intersections

Estimation of delay at signalized intersections is a complex process and depends on a number of parameters, among which the degree of saturation (x = v/c) is the most important. This paper presents a new methodology for estimating delay parameter ?, and proposes an analytical delay model for signalized intersections that considers the variation in traffic flow. Unlike the existing delay models in the literature, the delay parameter k is not a fixed value and is expressed as a function of the degree of saturation. The proposed model is applicable to the entire range of expected operation including highly oversaturated traffic conditions. A comparative study of the proposed model against the existing models was performed to verify the improvements by the proposed model. Later, the TRAF-NETSIM (Traffic Network Simulation) microscopic simulation model was used in the calibration and verification of the new delay model for oversaturated conditions. The simulation was conducted in 3 consecutive time periods to reflect fluctuation in traffic demand. The relationship between the simulated and proposed delay model results were analyzed for 48 different scenarios. ©TÜ? ITAK