Abstract: speed identification is becoming an important project of road traffic accidents forensic. Unilateral accident of vehicle hasn’t attracted attention because of its particularity. The main types of unilateral accidents include collision guardrail, rollover and reconnects. Unilateral vehicle collision speed identification principle is mainly based on the law of conservation of energy. After analyzing commonly used identification formula for three types of unilateral accidents, the basis points of their evidence collection were explored, including measure methods for guardrail deformation, vehicle deformation, the radius of the circular motion and fall flight distance. It was pointed out that measurements of the other elements of traces and evidences on the accident scene can play the role of secondary prove for the speed identification

摘要： 车速鉴定正成为道路交通事故司法鉴定的重要项目。单车事故由于其特殊性，其相关尚没有引起注意。单车事故主要类型包括碰撞护栏、侧翻与坠崖等。单车碰撞事故车速鉴定原理主要是基于能量守恒定律。在分析三类事故常用鉴定计算公式基础上，对其取证要点进行了探究，包括护栏变形、车辆变形、圆周运动半径、坠车飞行距离等测量。并指出其他事故现场痕迹物证要素的测量对于车速鉴定可以起到辅助佐证的作用。

关键词: 车速鉴定 单方事故 交通管理