Fight it out?
The very good advice to never leave your shield/weapon/vehicle while you still have gas and a route to escape has been very clearly driven home.
I'd like to address the idea that I've heard shared a number of times that maybe you and the accosting person should just square off and go bare-knuckle, "mano 'a mano."
Someone once said that anyone who thinks that it may be better to fight it out man-to-man -- and take your licks if you can't best the other guy -- watches waaaay too much TV.
Real-world fights, beatings, and other non-firearm violent interactions very often lead to fatality. And if they don't lead to a death, then often to crippling and/or job-impairing injuries that take months/years to heal if they ever do.
You may lay the guy out cold with a swift haymaker and then disengage like a gentleman -- and the two of you part ways with your best Cagney one liner, "let that be a lesson to you, see!"
Or he may be a hair faster, or stronger, or quicker, or more skilled, or just more determined, and you end up with serious bone and internal organ injuries or brain damage, which will end your life as you know it.
Or the other "gentleman" may see your offer to get out and engage in fisticuffs as a perfect opportunity to draw his own weapon and kill you without bloodying the seats in "his" new truck!
Violence is deadly. Force is deadly force. Never give up an advantage. Never treat assault as a risk you'll face willingly.
Drive on, disengage, make every attempt to break contact. If all else fails, I would even go so far as to recommend announcing and displaying your weapon if that's what it takes to convince the assailant to back off. If someone sees that you are armed and is still willing to bring the fight to you, it is time to shoot. When he closes that distance, your continued existence is a roll of the dice.