Here's another twist: my under 21 son needs a rental car for a roadtrip in the USA for 2 weeks. Since we're USAA members, it seems certain he can rent the car from Hertz and drive. But he's travelling with his friend, also under 21. Is there any way -- for free, or at a low price -- that his friend (not a USAA member) can drive? It would be unfortunate if economics and/or fiscal responsibility would require my son to do all the driving.