Abstract: 

This study reports on an in-depth analysis of the properties of Gipps' car-following model. Certain properties of the model are investigated and the need of specific additions to the model is identified. Gipps' car-following model is rather important as it comprises the traffic model of several traffic simulation packages; and the analysis performed in this study determines the actual dynamics that govern model formulae. First, the relationships for the maximum acceleration and deceleration values the model produces are identified. Results indicate that model relationships are such that a vehicle could end up braking harder than its desired deceleration, hence a constraint has to be set. Furthermore, relationships between vehicle acceleration and speed are established. Second, further additions are proposed to allow the model simulate traffic at signal-controlled junctions. These additions include providing a definition for a queueing vehicle and speed manipulation to achieve the calculated saturation flow of simulated junctions.