REO with some artistic license...
Depending on the level of threat- utilize the ground, grill, grape- stepped, use of force protocol, with liberties to accelerate to the appropriate response, based on the perceived threat.
Step # 1 / Ground- a warning shot may be placed into the ground between the shooter and an approaching suspect threatening target vehicle as a deterrent message.
Step # 2 / Grill- a warning shot may be placed into the grill of an approaching threatening target vehicle as a deterrent message.
Step # 3 / Grape- a lethal force shot into the head of a driver of an approaching deadly threat target vehicle as a self defense deterrent.
REO is ROE