Watch videos of police shootings. Often officers will take cover by hiding behind cars. Sometimes they even return fire by shooting under the car. This can be an excellent strategy since car bodies are thin sheet metal and provide little cover. There are some important tactical considerations when shooting under a car. The view of the suspect may be quite restricted, but if you have a clear shot, then this can be an excellent tactic.
Remember that many roadways are higher in the middle than they are along the curbs. Make sure you have a clear shot at the suspect; you don’t want to hit the center of the roadway. Watch the underside of the car. The movement of the slide can break sights off the weapon, bend them or knock them out of alignment if they strike the underside of the vehicle. It’s not a good idea to knock you sights off during a shootout.
I teach officers to try and keep the same grip on the gun in the prone position as they have in the standing and kneeling positions. No need to reinvent the grip simply because you are lying down on the ground. If you need to in order to get a good shot, lay on your side rather than on your stomach. If you lay on the same side as your pistol ejection port, make sure to keep the slide at least an inch if not two inches from the ground. You don’t want to induce a malfunction because your spend casings can’t eject. Make certain of your sight picture, it is often the case that shooters will tend to ignore the rear sights, so make sure you have a good sight picture when shooting from under a car. Shoot from the location that gives you the advantage, that’s what the SGT Says.