Do Cars Stop Bullets?

Therefore, it is reasonable to wonder whether a car can stop bullets and whether using a vehicle as cover to protect yourself is a good idea.

Cars, trucks, vans, and other types of four-wheeled motor vehicles are ubiquitous on the streets, and it is tempting to think of them as viable pieces of cover if you ever ended up in a gunfight or under fire from an active shooter.

However, despite their size, most cars are a liability for protecting yourself. Remember that concealment is not cover; even if you can hide a good percentage of your body behind something, it does not mean the bullet cannot pass through, potentially causing injury or death.

Although cars offer some concealment from an aggressor’s view, the ballistic protection they provide may vary from passable to nearly non-existent, depending on where the bullets are coming from and your position.

In other words, using the wrong part of a car as a piece of cover may be no better than being exposed.

If you have to use a car as a piece of cover, it is critical to learn which parts are the most suitable for protection against incoming projectiles and how well these projectiles will penetrate upon impact.

Behind the Trunk

Provided it is empty, the trunk is one of the parts of a car with the largest amount of empty space, providing, in turn, the lowest amount of practical protection from fire.

If you were to hide behind the trunk on the right side of a car, with someone shooting at you and sending bullets into the left side of the trunk, the bullets will likely penetrate clean through and hit you.

Virtually every commonly-available caliber will pass through a car trunk, with the notable exception of .22 Long Rifle and most birdshot and buckshot shotgun shells, which should be stopped or severely slowed down by the car’s body. Even then, this is an unreliable proposition, as some pellets or .22 bullets may still carry lethal amounts of energy.

If the trunk contains multiple heavy or dense objects, such as groceries, bullets may be slowed down or deflected enough to prevent complete penetration, but you should not count on it.

Behind Car Doors

Car doors offer slightly more from incoming projectiles than the trunk due to reinforcing elements and mechanisms (stereo speakers, window mechanisms) inside of them.

While they are marginally better at stopping pistol bullets, they still have a good chance to penetrate entirely through two car doors, potentially injuring people inside or hiding on the other side.

Note that even if a bullet does not directly strike the window, the concussion created when hitting a car door may shatter or break car windows, projecting broken pieces.

Although you may have seen situations where police officers take cover behind open car doors, they do not use the doors as protection from gunfire; they do so to create a makeshift rest to give themselves a more stable shooting position.

Behind the Engine Compartment

The engine compartment of a car contains the engine block, which includes parts made of hard materials such as aluminum, magnesium, and steel. The engine block offers the most effective cover from firearms, as even the most powerful rifle calibers have trouble penetrating through an engine.

Hiding behind the engine compartment is the safest option if you need to use a car as cover. However, keep in mind that gunfire is likely to destroy the engine and cause spillages of fluids such as engine oil, radiator coolant, power steering fluid, or gasoline. 

If the engine was running before being struck by bullets, it might also start smoking or burn, potentially creating a car fire and presenting a considerable safety hazard.

Behind the Wheels

Although the tires are rubber, the wheels use aluminum alloy, the brake discs typically employ cast iron or composite metals, and the car axles are made of some type of steel, such as carbon steel or chrome-molybdenum steel.

These hard metals offer excellent ballistic protection, resistant to powerful rifle calibers, and near-impossible to penetrate completely with commonly-available firearms.

Depending on the vehicle’s size, the wheels and axles’ dimensions may present more or less protection from gunfire.

Longitudinal Cover

All the scenarios described above imply a situation where the attacker is shooting from one side of the car while you are taking cover on the other side of the vehicle, with the bullet’s trajectory being transversal (from side to side).

However, it’s also possible the bullet’s trajectory may be longitudinal instead (from front to rear or rear to front). In such a situation, the car’s entire length serves as your cover, but the protection level may not be the same, depending on your position.

Hiding behind the car may seem like the safest proposition, as it places the engine ahead of you. However, unless the vehicle has high ground clearance, the engine’s relatively low position may mean that the bullet trajectory could miss it entirely.

If the bullet passes through the windshield, the only elements on the way will be the seats, the trunk, and objects in the middle.

High-velocity rifle bullets can pass through all of these elements and retain enough energy to cause lethal injuries.

The safest position is to hide in front of the car, using the engine compartment as your primary means of protection. By crouching behind the front bumper, the bullet trajectory should be intercepted by the engine, if not by every other element on the way.