The National Highway Traffic Safety Administration (NHTSA) has proposed building the National Advanced Driving Simulator (NADS). As proposed, the NADS will move the simulator's cab so that realistic motion cues are provided to the simulator's driver. It is necessary to determine the motion base capabilities that the NADS will need to simulate different severities and types of driving maneuvers with adequate simulated motion fidelity.The objectives of this study were (1) to develop tools, based on existing vehicle dynamics simulations, simulator washout algorithms, and human perceptual models, that allow required motion base capabilities to be determined and (2) to use these tools to perform analyses that determine the motion base capabilities needed by the NADS.The NADS motion base configuration examined during this study, which may not correspond to that used when the NADS is actually constructed, includes an X-Y Carriage capable of large excursions. Riding on top of the X-Y Carriage is a Hexapod that can perform smaller motions in all three directions and generate rotations about all three axes. On top of the Hexapod is a Yaw Turntable which allows for continuous yaw rotation. The simulator cab is on the Yaw Turntable.Ideally, NADS will be able to simulate motions with sustained accelerations of up to 0.8 g with a scale factor (a multiplicative factor applied to all accelerations and rotations) of at least 0.50. Meeting this specification for the washout algorithm studied and the motion fidelity requirements used requires a motion base that has ±120 feet of X-Y Carriage travel. Building a motion base of this size will be an engineering challenge.It may be acceptable to use a scale factor as low as 0.375 with the NADS. Using the lower scale factor drops the required X-Y Carriage travel to ±45 feet.This study also found that a limited (as compared to continuous or unlimited) rotation Yaw Turntable may well be adequate for the NADS.