HOV - Mileage - Tax Incentives - GA

Hi,
I can't speak to the GA law queries, but I can address the 2nd question about hills and city mileage. Hills in general usually don't hurt mileage, in fact some people report better mileage with hills. Hills with stop signs at the bottom are troublesome though since you're forced to dump all the energy of the hill by the time you reach the bottom and the battery can't take it fast enough (so the brakes handle the majority of the hill energy).

The type of city mileage the EPA measures (and reported higher than highway mileage) is a pair of long (about 20 min.) trips, one with a cold engine start and one with a warm engine start. The average speed is around 40 MPH with a few well spaced stops in between. And the A/C is turned off. The kind of city mileage you may be experiencing (short trips, stop & creep, A/C running) may not be so ideal, so you can easily get worse mileage. This is true of most cars, but more noticeable in the Prius since it's presented in your face instead of just getting buried in the highway mileage between fill-ups.

You should also check your tire pressure. The recommended 35 psi front and 33 psi back should be considered a minimum. The tires are rated to handle 50 psi, and will get better mileage if you increase the pressure. But you might not like the ride and/or handling, so find a pressure that suits your needs.

Good luck with your fun new car.

Hills - good or bad for mileage?

Jim, yes, driving technique makes a difference. I think it is possible for hills to improve mileage, traffic and safety permitting. What I do is this: apply power to the car on the upslope and maintain speed or lose a bit on the downslope. On the upslope, the engine is going to run hard and is efficient at this time, so power is "cheap" and by using more you increase efficiency and it actually gets cheaper. On the downslope, you ideally want to free-wheel with the engine off and use no power at all (this would be pure "pulse driving"). But the Prius allows you to let the engine go off and then bring back enough pedal pressure to maintain speed using battery power. Although this power is not "free", as some people think, it will be replaced "cheaply" when the engine starts on the next upslope.

After a while, you can learn how to apply a similar strategy in traffic surging between stop lights. I have a 13 mile commute in traffic with speed limits from 30 to 50 m.p.h. and about a dozen stops. This morning when I pulled in to work, the consumption display reads 55.1 m.p.g., which I believe to be 52.6 m.p.g. actual.