It was in 1967 when the stereo-camera system was introduced to the traffic division of the National Police Agency in Japan. By the end of 1971, every prefectural police adopted it, and today 256 stereo-camera cars and 76 stereo-plotting instruments are under operation all over the country. They have made great contribution to the scientific inspection for the traffic accidents resulting in injury or death. Most of the stereo-camera cars are settled in the police stations and most of the stereo-plotting instruments are settled in the headquaters of the police. In 1977, exposured were approximately 90, 000 scenes among in the traffic accidents, a stereo-camera car dealt with about 350 accidents and 30% of them were mapped on papers by the stereo-plotting instrument. There exist principal advantages in stereo-camera system as follows: 1. Accurate inspection of real condition and rapid field activities 2. Scientific measurement of damaged car on the traffic accident spot 3. Application for the analysis of traffic accident 4. Contribution for the Synthetic policy of traffic safety 5. Application for the identification activities on the spot in complex and massive affairs or accidents On the other hand, there exist problems of stereo-camera system in the National Policy Agency, deterioration of the stereo-camera, education of freshmen for the operation as well as technical improvement of equipments. The benefits of stereo-camera system are extremely powerful over versatile fields in police activity.
A diagram has been annexed to the spot inspection record of the traffic accident or incident were drawn up with measuring-tape heretofore. We introduced the method applied with photogrammetry partially into the police since 1969. Sixteen (16) of the stereo-camera (base length-120 centimeter) were provided and came into use for the investigation of traffic accident and incident at present. These methods have produced some good effects on speedy spot investigation, quick settlement of traffic stagnation along with specialization and efficient investigation and prevention of traffic policemen from traffic accident. These stereo-cameras are utilized in another field actively in order to use them efficiently. Take some sample of our practical use of them, these instrument are utilized for investigation of the road structure at the intersection of traffic accident frequency or scheme of road improvement in order to root out of traffic accident. Furthermore, they are employed in the inspection of the ultimate causes of accidents due to the road administration. Inspect the desruction of the“motorcar to motorcar”accident and make out the identification materials to study the cause of accident. Write out the study documents of the cause of“roll-up”accident by the large-sized vehicles to study of the prevention measures of such accident. These instruments produced much good effects on calculation of area and volume required by the nature of the criminal cases. In recent years, the stereo-camera (base length-20 centimeter) had been developed. It is expected that it will be utilized to make correct dianognosis a part of casualty (sufferer) . A system with stereo-cameras as axis (main-instrument) produced low cost, simple operation, almost unnecessary for control point surveying and less influence of the weather as compared with the aerial photogrammetry. As the stereo-camera has like this advantages, it is presumed that there is enough room to be utilized widely in the public. It is ten (10) years since the police had introduced the photogrammetry, we believed that we should make every efforts to extend practical use of the instrument.