Incorporating intelligent speed adaptation systems into microscopic traffic models

Intelligent speed adaptation (ISA) systems are incorporated here into microscopic traffic models; Gipps´ car-following model is discussed and the appropriate model parameters that need to be modified and additional ones that may need to be introduced are investigated. Driver behaviour under three different functionalities of ISA, namely informative, warning and intervening, is investigated through a driver simulator experiment. The impact of ISA systems on driver behaviour is a complex matter because it varies both among drivers and under different scenarios. The main parameters that capture the ´reaction´ to the system are identified and are quantified through model parameters. These are driver speed, acceleration, deceleration, reaction time and effective size of the vehicle, and are estimated following the analysis of the simulator data. The resulting values confirm the necessity of parameter modification. The analysis performed for the incorporation of ISA into the traffic model indicated that a prerequisite of successful implementation is a deep understanding of the model parameters and dynamics.