This report presents the methodology and results of the independent evaluation of a prototype integrated crash warning system for light vehicles as part of the Integrated Vehicle-Based Safety Systems initiative of the United States Department of Transportation's Intelligent Transportation System program. The system integrates rear-end crash, curve-speed warning, lane change crash, and lane departure warning functions. The goals of the independent evaluation are to assess the safety impact, gauge driver acceptance, and characterize the capability of the integrated safety system. The evaluation is based on naturalistic driving data collected from a field operational test using 108 subjects who drove 16 passenger vehicles equipped with a prototype integrated safety system and a data acquisition system. The test subjects accumulated over 213,000 miles during a 12-month period throughout parts of southeast Michigan. For each driver, the test period was divided into a 12 day baseline condition with the system disabled and a 28 day treatment condition with the system enabled to compare the effect of the system on driving performance. The results of the analysis suggest that driving with the integrated safety system improves driver behavior and increases driver safety, that drivers feel that the system provides a safety benefit, and that the system alerts had a high degree of accuracy. This report delineates the methodology of the different analyses and discusses their results.