I get around 17.5 to 19 mpg with about two thirds city third highway driving. The city mileage is decent considering that in San Diego you will wait at every stoplight, er, traffic light on your trip. San Diego doesn't believe in efficient, smooth flow of traffic.

On a trip to Las Vegas last year I averaged 24 mpg to Barstow (about 3/5 of the way to Vegas from San Diego) and 25 mpg from Barstow to Vegas. I thought this was excellent since highway construction caused stop and go traffic for several miles on both segments of the trip, and when past the construction zones, I was doing 80 (just staying with the flow of traffic - to go any slower is to risk being rear ended!).

Brent