When I was harrassing the pubic in my beat up old FJ-40, the fuel gauge was almost useless. S&W gauge and sender, by the way. So I nearly ALWAYS had a Jerry can on the back.
One day going across the "long bridge." Here's the wife of the local Shell oil distributor out of gas in her 70's Lincoln Continuous.
By the way, I'm not too damn sure she ever paid me back for that, either.