There are no steel ball dropping everywhere on public roads, why is the steel ball test needed under CNS 13762?
The back tires of large truck are normally combined in pairs, and irregular sizes of stones may stuck between the gaps of two tires; when the truck travels at high speed, the stuck stones can run directly over the reflection marks, and the consequence can be simulated via using steel ball falling freely from certain height. Should the impact can be sustained from a steel ball with certain weight, falling from certain height, the glass marking reflector under direct impact of vehicles with stuck stones would not break easily or create many holes that effects reflecting functions.
