关键词: 车辆, 交通事故鉴定, 物证, 痕迹, 原则和方法

Abstract: Combined with practical cases， the principle of traffic accident examination is discussed from the following aspects： vehicle technology examination， traffic accident traces identification， alcohol analysis， etc. The principle can be briefly described as to investigate the specific characteristics of an object with scientific theories， data and common sense， and thereby make it an evidence to prove the truth of an accident. The key point of traffic accident examination method is to let the evidence reveal the truth. Material evidence itself has many characters and only those related with facts are valuable. Forensic experts need to discover the features which could reveal the facts with their knowledge and experience. 

Key words: vehicles, traffic accident examination, material evidence, trace, principle and method