It accounts for 37~70% of autopsy cases of road injuries. The performance and degree of injury depends on the road surface, the kinetic energy transmitted by the car to the human body, the posture and clothing of the human body. ? The impact of the front and rear of the car on the human body will not only cause direct impact injury, but also make the human body fall and fall, and even cause injuries and fractures of the upper and lower limbs in severe cases. When the speed is high, you can also knock people out for a considerable distance before landing. When the human body is directly hit by a car from behind, it can first cause back injury, and then fall forward in front of the body to form a fall injury. After the human body is scooped up by the front of the car, it can slide from the edge or side of the car. When the speed is high, it will slide from the roof to the rear of the car and fall to the ground. If the buttocks touch the ground when falling, it can cause sacroiliac joint fracture or dislocation; If the shoulder or head is tied to the ground, it will lead to shoulder or clavicle fracture, as well as skull fracture and intracranial injury. The lateral side of the skull, that is, behind the ear and above the ear, is most likely to be injured first, resulting in a fracture of the temporal parietal bone, which often extends to the skull base, forming an epidural hematoma and contralateral brain contusion. Sometimes, because pedestrians walk on the road between two parked cars and are knocked down by passing cars, there is no bumper injury, only head injury caused by falling backwards. Apart from fractures and falls, the above injuries often form scratches on the skin surface because the human body receives the kinetic energy of driving vehicles and has a certain speed when contacting the ground or other objects. In addition, the distribution of falls and direct injuries is also different, that is, bruises and contusions are often formed in exposed parts of the body (such as hands and face) or thin clothes. It can be distinguished from direct impact injury.