Which symbol on a regulatory marker indicates hazards such as rocks or stumps? green square?

The symbol on a regulatory marker that indicates hazards such as rocks or stumps is an Orange Diamond. Regulatory markers are types of non-lateral markers such as white and orange markings that are used as navigation aids that give directions, warn of dangers and marks controlled locations. Orange diamond shapes warns of dangers such as rocks, stumps or construction.

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.