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The marking mechanism were considered again, by pressing four kinds of fiber textures on two kinds of plates for automobile coating films. And the following results were obtained. 1. Fiber texture marks was the depression of the coating top layer. 2. The marks which resemble closely to those in traffic accidents could be formed on the following conditions. (1)Contacting time for fiber with the plate was 0.005∼0.01 sec. (2)Pressing vertical load for fiber to the films were 3.6∼9.1 MPa. (3)Friction coefficient between fiber and coating films was ca. 0.3∼0.5. (4)Sliding length for fiber on the films was ca. 0.018∼0.063 m. 3. The marks were influenced by the top layer of automobile coating films, fabric construction of cloth and another conditions. For example, metallic coating films which contains the top clear layer were printed more easily than the solid ones.

Elucidating the formation mechanism of various marks and phenomena, which we may encountered in traffic accident reconstruction, may contribute to not only broad traffic safety but also the improvement of various products. We considered the reappearance of the marks and phenomena are most important for the first step of the elucidation. In this report, the real cloth texture marks printed on the door of crashed passenger cars and also the seat of crushed motor cycle and the like are showed. And more over, the marks which could be reappeared experimentally in our laboratory are showed. After experimental reapperrance of cloth texture marks on passenger car-door and motor cycle-seat and so on, it became apparent that following three phenomena should happen instantaneously for the printing of the cloth texture marks. Namely, (1) Surface temperature rises in the region of the material-melting point by friction between cloth and material. (2) The cloth should be stopped in an instant. (3) The cloth should be pressed.

The basic idea of the prediction is founded on our previously published theory, in which the vapour lock is mainly caused by the bubble growth below the brake-fluid boiling point. According to this theory, a brake pedal becomes spongy due to the bubble growth, and fluid pressure may be lost upon further growth. Hence it is most important for drivers to be able to determine the beginning of the bubble growth in a hydraulic brake because they can predict the vapour lock. Therefore, we developed an alarm device for vapour lock, which can sense the bubble growth, using a simple sensor with 2 short conducting wires embedded in disk calliper housing. Using this device, we are altered to bubble growth in the disk calliper housing by the light of the alarm lamp. In this report, the outline of this alarm device and the significance of the adoption of the device in automobiles are explained.

In order to clarify the filament surface color for accident reconstruction, the experimental destruction of seven kinds of light bulbs was carried out by changing the time between the light bulb power off and bulb rupture. The following results were obtained. (1) According to the time, the oxidized color changes to dark grey, green, blue, purple, yellow, and light grey in this order. (2) The relationships among the time, color index number alloted to a typical filament surface color, and the light bulb's rated consumption of electricity were obtained as an approximate equation. (3) Elapsed time starting from the power off can be derived on the basis of the surface color or an approximate equation. (4) The oxidized color is very useful for traffic accident reconstruction. By means of this information along with conventional findings, drivers' behavior at the accident may be postulated more precisely.