This paper assumes that in an intelligent transportation system (ITS) traffic control environment, traffic control systems will be able to track vehicles individually in a traffic stream through automatic vehicle-specific identification (AVSI). As a vehicle passes an AVSI roadside reader site, it is assumed that the reader records the arrival time and type of detected vehicle. The reader sends the information received to a local microprocessor-based traffic signal controller. The controller's built-in signal control logic then uses the information to adjust traffic signal timing to reflect the present traffic stream's characteristics. Given this assumed capability, a simulation model is developed to evaluate the benefits of the use of AVSI. To make use of AVSI, a new vehicle-specific adaptive (VSA) traffic control logic is built into a simulation of an isolated intersection. Through the simulation, identifiable, measurable, and significant benefits are found from the use of AVSI in adaptive traffic signal control logic when the incorporated VSA control strategy is tested against the pretimed control system.