This report presents the results of an independent evaluation of the Automotive Collision Avoidance System (ACAS). The ACAS integrates forward collision warning (FCW) and adaptive cruise control (ACC) functions for light-vehicle applications. The FCW detects, assesses, and alerts the driver of a potential hazard in the forward region of the vehicle. The ACC provides automatic brake and throttle actuation in order to maintain speed and longitudinal headway control. Through the integration of these two functions, ACAS is intended to improve automotive safety by assisting drivers to avoid rear-end crashes. To accomplish this goal, the ACAS must also prove useful and acceptable to drivers. The Volpe National Transportation Systems Center conducted the independent evaluation of the ACAS based on data collected from a field operational test (FOT) and from an independent system characterization test. The goals of the independent evaluation were to: characterize ACAS performance and capability; achieve a detailed understanding of ACAS safety benefits; and determine driver acceptance of ACAS. Data were collected from the ACAS FOT that employed 10 vehicles using a total of 66 drivers that included three age groups (younger, middle-age, and older) with equal numbers of male and female drivers.