Interestingly, our policy explicitly prohibits shooting at the occupants of a moving vehicle UNLESS they are pointing a gun at or shooting at you. Use of the vehicle alone as a deadly weapon (running folks down) is specifically NOT justification to shoot. This in a city where years ago a disgruntled Afghan refugee nutjob when on a "Runnin' folks down" spree. When it is pointed out that this policy makes stopping such an individual more difficult, the response from policymakers is basically "Yes....that is a conundrum. Hope it works out!"
Recently the policy was changed to include Vehicle Deflections as a use of deadly force....so at least we have that now.