Vehicle forward collision imminent braking (CIB) systems have been equipped in high-end passenger vehicles by many auto manufactures. Due to the complex nature of the CIB technology, the features and performance of various CIB systems differ significantly. As to date, there are no standards to evaluate and compare different CIB systems. This paper describes a systematic methodology for the evaluation of CIB systems which include both braking and warning. The percentage kinetic energy reduction is used as a common unit to allow the evaluation of the performance of both CIB braking and CIB warning. The information collected from some ongoing vehicle active safety testing projects will be used to validate the proposed methodology.