As one of the key technologies to improve safety of large trucks, pre-crash safety technology (PCS) was studied. PCS is the system which automatically activates brake when a collision is unavoidable.

From the accident analysis, it was found that collision to the stationary vehicles and accidents on expressways shall be considered in the study. To cope with the accidents on expressways where collision speeds are usually high, the PCS system needs to detect the objects and apply brake from a long distance. To achieve this, sensor shall be tuned to enable the sensing from long distance, however, generally this can result in difficulties to clearly divide real objects on the road and something on the road side especially at curves. If we can limit the activation of the system only on expressways, there is possibility that this can be improved. Because on the expressways, traffic lanes are wider and thus road side objects are a little far from the center of the traffic lane, and radius of curves are more than certain value. Activation timing of the brake shall be decided so that the driver does not place too much trust in the system. For this reason, the brake shall not be activated when there is certain possibility that the collision is avoidable.