[mrv]

This is a rather specific question for driving in California.

Has anybody experience in driving the Prius on CA-5
over the Grapevine? (Summer and Winter)

A few posts over on the toyota-prius
yahoogroup about it. one or two made
their way into the FAQ section about
hills.

You should do far better than most
cars going up that pass. (Depends on
how many people and luggage you have in
the car and the speed you're going.) Don't
expect cruise control to hold out for the
entire length of the pass, though.