I've often wondered why ALL police cruisers don't have some sort of armor either embedded within or attached to the outside of both front doors of the vehicle. Maybe even thicker glass on the door windows.
Ok, cost.
I don't see how it could be any more expensive than all the other gear & gadgets on the typical cruiser. Even so, would it not be worth it for the officers to have at least some measure of protection in such a scenario?

If there'd be no space within the car door for armor....then the doors outside could perhaps be made of 1/8" steel instead the typical "soda-pop-can" metal seen on the average car.

Russ