Emphasis is given to the immediate evaluation of the accident scene, taking care not to contaminate or destroy evidence (especially tire tracks), and the involvement of forensic and other experts. Injuries, vehicle interior and exterior damage, and tire tracks provide an overall picture and can often indicate where an accident victim was seated in the vehicle. Fiber, blood, skin, and hair samples should be taken from the vehicle's interior and compared to those found on the vehicle occupants. Fiber traces on the interior of seat belts can be matched to the occupants' clothing. Shoulder harness marks provide good clues regarding occupant position; specialists should disassemble and examine the belt unit for damage. The position of the front sear, rear and side-view mirrors are important in revealing the size of the driver. Dirt on the floor mats may be traced to occupant shoes. Photographs should be taken from different angles to reveal the whole picture and important details. If possible, specialists from various fields should be called to the scene. An open exchange of information and findings during later evaluation is essential to the process.