I live in SoCal (Long Beach). My hwy speed on the frwy is 64 using CC. Always, unless traffic is locked. That's when my milage really goes up.

This summer, in the mid-west and Canada, we drove the US hwy and state/provincial routes. Sometimes even county. Speeds around 55 (again, where I can CC) do result in better milage, with the best being around 30 or so while supporting a bike ride.

You are right in your observation about speed on the SoCal frwys. Unless they're really jammed up, I'll drive the slow lane. Or, if I can, get over into the car pool lane.

 

The cc tends to over assume on the slightest hills, it will rev higher than needed as you crest the top.

As a person you know when the cars going to crest and start downhill do you can ease off the gas and let momentum carry you but the cars computer doesn't know and will continue to provide more power all the way up.

 

About 80% of my miles are with cruise control set between 50 and 53 miles per hour.
I commute during the beginning of the rush hours so traffic is NOT zooming by me at 75 miles per hour anyway.

Almost no hills and mild weather.
I always drive alone and in the right-most of 4 to 6 lanes.
I never use AC.

I am positive peak MPG is somewhere below 50 miles per hour but I think I will be killed if I go 45 miles per hour on Southern California freeways.

I drive faster and less efficiently now than a couple months ago when I got two tanks over 71 MPG.
That was way too much trouble, but it was fun to see what the car was capable of given my driving conditions.

People say CC is bad for their MPG but they do lots of stuff I don't do like drivie with the load or pay attention to the RPMs, yet I'm getting a lifetime avergage of 64.5 MPG over 36 tanks.

 

Since I don't see a MPG penalty until I get over 65mph, I will typically drive at 60 to 65mph. If there is a pack of cars going 70mph, then sometimes I will trail them a few carlengths behind at 70 to take advantage of their cumulative draft. If there is a strong head or tailwind, then I will adjust my speed down or up to maintain an airspeed under 65mph. My car doesn't have cruise control, but do have a hand throttle that I use for DWL. At these speeds on the highway, I typically get mid-70 to mid-80's mpg on gently rolling terrain and low to mid 90's on flat terrain.

 

Basjoos - LOL, You and Kenny are at the extremes... him slow with CC and you fast w/o CC and both knocking out big FE numbers month after month...

 

That has been my experience too. The CC wouldn't think twice of sucking down all the gas it could, just to keep the speed at exactly its setting while going up a hill. However, I try to manually limit the "gas sucking", and allow my hybrid to slowly loose speed going up a long hill. Yea, I might be down to 50mph at the crest, but that's life.

If I am lucky, there is an overloaded truck up ahead, and I can "blame" my slowly loosing speed on it.

When I am on I287, I use the extra slow-truck-lane on many of its uphill stretches.

 

Hi everybody!

I just got my '08 Prius last week. I was just getting used to driving it about mid-way through my first tank of gas when I started paying attention to driving habits and corresponding gains/losses with regards to the energy and consumption menus.

I noticed a drop in fuel economy when I went over 60mph - especially when I went 65mph. I dropped my speed down to 55mph and saw a huge improvement. Now I set my CC at 55 and let everybody pass me on the interstate. The right lane is my new friend! It takes some definite patience to break the habit of going between 65-70mph like I have been used to traveling for years now. However, for my first tank of gas, I drove about 538 miles and got something like 53.8mpg average.

Since I started driving 55 on the interstate using CC (haven't learned any other Prius driving techniques yet), I've driven 333 miles and I still have half a tank of gas. I've also averaged 55.4 mpg on this tank. I'm expecting to get close to 600 miles out of this tank of gas.

 

Hi Jim,

Welcome to the CLUB!

You might head over to the Prius forum and read up the FAQ. This will give you some tips that will let you come closer to 65 mph and still get excellent mileage.

GOOD LUCK!
Bob Wilson

 

I drive 65MPH and about 100 yards behind large trucks, I get about 54MPG in my new, 2008 Prius.

 

Walt - the CC sucking too much gas going uphill argument always gets me confused.

Say you dont use CC and you start up a hill at 60mph, crest at 50mph then accelerate back to 60mph at the base of the other side. Maybe your average speed was 55mph in this case.

Then you take the hill using CC set at 55mph. Maybe you burn a little more going up, but less going down than the non CC case.

Dont get me wrong, I dont like CC "flooring it" up a hill either and I will usually drop the CC setting down a few miles per hour as I go up the hill.