The Sustainable ITS Project at the University of Tokyo has developed "the Universal Driving Simulator for Human, Vehicle and Traffic Research". This driving simulator can be used for research involving ITS, vehicle development and evaluation, including human factors of driving in traffic. The simulator can be connected to a macroscopic and microscopic traffic simulation system called KAKUMO. KAKUMO can generate virtual traffic in the simulator scenario in real time, with up to 100 surrounding vehicles created and controlled independently. Before applying this simulator to experiments, empirical calibration and validation will be required. In this paper, the evaluation of the traffic simulation component of the driving simulator is described. A pilot experiment was carried out to start the validation of the driving simulator, comparing the driving of an experimental vehicle on a real road and driving the same road in the simulator.