One is comprehensive.
It is necessary to comprehensively measure and record all elements related to traffic accidents, including roads, buildings, facilities, signs, markings, vehicles, traces and attachments, road traces, scattered objects, etc. And all the elements must be related, that is, they cannot be isolated, so that the whole scene can be restored in the future.
The second is meticulous.
It is manifested in the detailed inspection of the area, shape and height of the traces of vehicles and other objects, and the direction of stress and the direction of traces are clear; For tire marks on the road surface, it is necessary to distinguish between rolling marks, embossing marks, dragging marks and sideslip marks; For pavement scratches, it is necessary to find out which part of the vehicle or object is formed with the pavement, and carefully check the various forms, starting and ending points and changing points of the pavement marks; Check the accessories on the surface of vehicles and objects; Investigation on human injuries, clothes, soles, etc. At the same time, determine the contact point, mark it with chalk, and determine the reference point around the contact point.
The third is measurement.
We generally use rectangular coordinate method to measure plain roads; The roads in mountainous areas are measured by trigonometry, and the measurement is carried out in strict accordance with the standard of Traffic Accident Traces Inspection issued by the Ministry of Public Security in 2005. These are all well known.
The fourth is inspection.
Check the gear position, lighting equipment, direction and braking ability on site. , and the inspection of wipers in some rainy days; The injured person went to the hospital to check the injured part, coat marks, etc.
The fifth is color fixation.
Extraction and preservation: all traces and physical evidence are fixed first and then extracted, fixed by various methods such as text narration, photography and video recording, extracted by special tools, and preserved in pollution-free paper bags and plastic bags. When necessary, the vehicle should be detained in the indoor parking lot. Common physical evidence such as scattered objects, documents in the car, shoes and clothes. Trace material evidence includes blood, hair, human tissues, clothing fibers, patent leather, etc. Of course, handprints, fingerprints, rubber and asphalt are rarely extracted, and some are inconvenient to extract.