Because having a bullet-free body is good for your health.
Amid the scary amounts of violence that police face on a daily basis, Ford, a company that controlled 60% of the police car market for the US in 2015, has announced that they will start offering optional bulletproof doors for its line of Police Interceptor sedans and SUVs. These doors will be able to stop armor piercing rounds in their tracks. It isn't commonly known but Ford has offered bulletproof doors on police cars since 2008, which departments opted to fit on 5% to 10% of Interceptors.
The old armor cost $1,500 per door panel and was only able to stop handgun ammunition. Not only will these doors make mincemeat out of handgun ammo, but they will also stop an AK-47's round in its tracks. The bulletproof doors have two layers, one on the outside made of ballistic grade tile and an inner layer made of aramid fiber, which is the material used in Kevlar body armor. When a bullet strikes the door, the ceramic tile shatters to dissipate the bullet's energy and then the fiber behind catches all the tile and bullet fragments to keep the lawmen and women safe. Ford decided to offer these cars to American police forces after cops in the Middle East and Eastern Europe kept requesting them.
The only (big) problem with these doors is that they do nothing to defend an officer if someone shoots the window above the door, but at least some protection is better than no protection. Want these bulletproof doors for yourself? You'll need to join the police academy because not only are these doors unavailable to the public, but old cop cars that have them are crushed to prevent criminals from getting ahold of them.