Minor semantic niggle -- police shouldn't run a car off the road in any situation where they *wouldn't* shoot. Firing a gun while maintaining control of a car and being able to actually hit a moving target at that speed is Hollywood stuff. Hitting a car with a car is easier because you're not dividing your attention.
But your basic point is valid -- trying to ram or spin out a fleeing vehicle is potentially deadly force, same as use of a firearm. And the same calculus applies -- is it necessary? Is it justified? Does it decrease the risk to innocent bystanders? Does it increase the risk to bystanders?
Yeah, when I said "couldn't" I meant "couldn't because the law wouldn't allow it".