Results of previous studies have indicated that an automatic/noncooperative radar braking system may provide a significant benefit in preventing accidents that may otherwise be caused by driver inattention or tardy driver response. However, one of the major technical problem areas in implementing the automatic/noncooperative radar brake system is in achieving sufficient target discrimination. This is necessary to allow rejection of non-hazardous objects and to maintain a sufficiently low false alarm rate while retaining recognition capability on all potential hazards.This paper presents the results of an experimental and computer simulation study conducted to resolve the effects of the various system parameters which may be significant to the target recognition problem. The target discrimination experimental study was conducted using an instrumented test vehicle equipped with an automatic/noncooperative radar braking system to gather parametric data under typical traffic conditions. The test courses selected for the experiments typify much of the high density, high speed, urban and suburban driving in the United States. The sensitivities of the various radar brake system parameters are also discussed. This work was sponsored by National Highway Traffic Safety Administration of the U. S. Department of Transporation.