The National Advanced Driving Simulator (NADS) system was designed to conduct driver centered safety studies. The NADS contains three major components: the Software Engineering Environment (SEE), the Simulation Development Module (SDM), and the main NADS (the real-time simulator. The purpose of the SEE is to provide an environment for development of the NADS software, databases, and scenarios. The purpose of the SDM is to validate scenarios before actual execution on the NADS. The full NADS contains all of the capabilities required for driver centered research using the general population, including a state of the art Scenario Definition and Control capability.