Granted, I've only had the car a couple of weeks but I've done the research on "proper Prius driving" and am trying really hard to break the 40 mpg barrier. Logically, there should be the same amount of downhill as uphill driving in San Francisco. Anyone in S.F. having better luck than me? At least it's better than the 15.7mpg (rated 21) in my Volvo V50 or the 12.7 (rated 15) in my Acura MDX. I'm hitting about 37.8 in my 2010 IV w/NAV.
The downhill savings compensates for the uphill fuel burn only when you are able to coast down without significant use of friction brakes or engine compression braking. Many of San Fran's hills probably don't qualify. In my area, I-90 over Snoqualmie Pass is shallow enough to get full compensation. The few steep sections are short enough to not fill the traction battery with regeneration. In contrast, the first 6 miles down the west side of Stevens Pass on Highway 2 don't allow much recovery of the fuel burned in the climb. It is a long steep descent in a single pitch, so regen fills my battery quickly and the engine screams in B-mode for the rest of the descent.
I filled up at the Costco in South San Francisco and reset the trip odometer. I was getting around 38-40 mpg. The on a trip up to Pt Reyes (while on that same fillup), I was able to get the mpg back up to 48 mpg. I think with short trips in the city you're also hurting your MPG's since the ICE runs for awhile at startup.
It is worth noting that the EPA City route is over 11 miles long at room temperature at 21 MPH average on level ground, so your mileage should vary. Fuel Economy Test Schedules
~40mpg sounds about right for San Francisco city driving. It's pretty brutal driving in the city with the traffic and the hills.
I averaged 46-48 mpg the first 1000 miles. Switched to 17" TC wheels. I am getting 42 Mpg now. If you like to get 46-48 mpg, you can have my Prius II. We can do a even trade....J/K
