[Mello2u]

I can think of two scenarios where shooting the driver of a vehicle would be justified and the issue is not one of the shooter moving to escape harm rather than shooting:
1) In defense of another, where the shooter is shooting to stop the driver from proceeding to harm others and the shooter does not need to move to avoid the vehicle. For example, where a driver has driven through a crowd killing/harming some and is proceeding on towards another crowd to do more damage.
2) If the shooter can not move without increasing the risk of great bodily harm or death, yet is still at risk of either/both from the driver and his vehicle/weapon. For example, a person "A" is pinned behind marginal cover/concealment (a vehicle) by multiple shooters and one of that group of bad guys gets in a car and accelerates at the object providing concealment.

There are likely more scenarios that I can't think of at the moment. But where a shooter of a driver of a vehicle is claiming self-defense, justification seems tenuous at best if the shooter actually moved to avoid the vehicle in the course of events.