A human factors experiment was conducted to determine the effects of warning sound type, speaker location, and age on the ability to localize the direction of warning sounds in a passenger vehicle. The purpose of these warning sounds is to alert a driver of potential roadway hazards detected by an in-vehicle crash avoidance warning device. Auditory localization of the warning sound was investigated as a means of indicating hazard locations relative to the vehicle. Four dependent variables were measured— response time, decision time, accuracy, and azimuth—to assess the speed and accuracy of localizing six different warning sounds from each of sixteen speaker locations. The six warnings were found to be appropriate for crash avoidance warning applications through a previous study. The localization task was performed in the passenger compartment of a stationary 1995 Ford Taurus sedan. Subjects input their responses through a joystick. The results of the study suggest that the implementation of localized auditory crash avoidance warnings could be beneficial in the timely identification of hazard locations in the vehicle environment. People can quickly localize the general direction of warning sounds (= 1 s to 1.5 s); however, localization effectiveness depends on the proper choice of warning sound and speaker location. Otherwise, potentially serious problems can occur if poor choices are made. The study was successful in identifying sounds and speaker locations that performed best and provides recommendations for speaker placement for each of six potential hazard directions for the vehicle tested. / Master of Science