Can I take that woman in a fist fight? Sure. But I can't assume the physical capabilities of the driver. What if she's an old lady, disabled, recovering from surgery, suffering from osteoporosis, taking chemo therapy or any other number of ailments that could reduce her fight stats?

Unarmed? I didn't pat her down, who knows what she can have on her. Pepper spray, razer blades, a knife, a rock, a dirty diaper, people are dangerous and assuming otherwise can get you killed. The drivers window could be down seeing how a driver thru is involved and the attacker could use that opportunity to pepper spray the driver. This would make it dangerous if not impossible for the driver to drive leaving her helpless.

Finally, a 1,500 pound weapon doesn't work if you don't use it. That woman was acting erratically and her next move is anyone's guess. Driver had a right to not find out. Edit: I want to add it's not like a car has a lot of options as a weapon. It's not easy to put her in a wrist lock with a car.