This paper presents a vehicle system simulator, AGVSim2, to be used in the evaluation of control strategies of real-time free-ranging vehicle supervisory controllers. The C-based discrete-event simulator is designed to be flexible so that many system configurations can be modelled. Also, the simulator allows for complex free-ranging vehicle manoeuvres, bidirectional flow, multiple vehicle types, and multiple loads on a vehicle. Instead of modelling the vehicle controller logic, the simulator is linked directly to the vehicle supervisory controller software. The simulator reports a variety of performance statistics and a trace of the system activities so that the performance of the supervisory controller can be evaluated. To improve the evaluation procedure, the simulator is also designed to be linked to an animation module that graphically displays the vehicle movements.