Typos happen, we all make them. The typo I made talking about the Slant 6 motor's 30° cant almost got me fired, after all. But sometimes they're just funny and maybe more revealing than you'd think, like the one in this Hertz ad.
It's been taken off Facebook already, and it is a pretty subtle typo. It took me a moment to spot it: I think they wanted that "H" to be a "G" in "MPH."
There's a big difference between fleet averages of 28 MPG and 28 MPH. One sounds like what a modern rental car fleet should be making, one sounds like what a rental car fleet would be doing right around the Depression.
Still, I bet if you actually did the math, the average speed of a rental car is probably around 28 MPH, with traffic and all. It'd probably be closer to 20, but you have to factor in all the people who rent cars just to hoon the crap out of them.
Don't be too hard on Gertz. Those letters are right next to each other on the keyboard, after all.