Sheared delay formulae for the TRANSYT traffic model: A review and calibration

The paper summarizes the general theory of sheared curves and gives a general expression for these curves. The use of sheared delay formulae in different versions of TRANSYT, a well-known procedure for area traffic control, is reviewed. A new set of sheared formulae for the TRANSYT traffic model to estimate random-and-oversaturation queues and delays has recently been proposed that opens the way to extend the TRANSYT program to solve time-dependent problems. However, the choice of the key parameter in the sheared formulae remains an open question that needs further investigation. In this paper, the key parameter is calibrated by means of a well-known microscopic simulation package, NETSIM, which was validated for a medium-sized signal-controlled network in Hong Kong. Useful results were obtained.