As a lefty, I have always tried to think about my strong hand, and holstered weapon coming up along side the driver side door, and having to fend off an in your face BG with my weak hand. Or bringing the muzzle to target up the door and canted "outboard" to engage. As a southpaw, I have to "adjust".
On longer drives, I unholster, and place the pistol in a centered position, and practice weak hand drills often. Especially drive up ATM's, which I avoid at night or in "questionable" areas. Or watch my mirrors, even at a Drive thru McDonalds, etc,...
If given a no time to respond scenario, I'm gonna get low and punch it. My reaction time to the gas pedal, is going to be faster, than drawing my weapon.
but variables always come into the picture. Rob, or MB would probably have a valid suggestion also.