310 mile road trip, 57.2 MPG. Details inside.

Hey there everyone. I just wanted to share with you the numbers I got on a recent trip. I traveled from North Alabama to Northeast Tennessee. A total of around ~300 miles mainly highway traffic. During this trip, however - There were some factors that would have actually made this number worse than it could have been. I was stuck in two traffic jams, each in hilly terrain. About 4-5 miles crawling at around 5-10 mph for both. Drained my battery and the engine had to kick in for a while to recharge them. Not to mention, the majority of the drive was done in heavy rain, which reduces mileage. Before you ask, here are some specs about how I drove and about my vehicle
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-80 lbs. of audio equipment in the trunk.
-ECO mode.
-Tires at 42/40.
-A/C set at 75, switching between recirculation and fresh air (1-2 notch fan speed), overcast and cloudy sky helped with the temperature. (not auto mode).
-Two adults (300lbs total), and luggage.
-Parking lights and/or headlights were on majority of the way.
-Wipers were also used about half of the trip.
-60/70 mph the majority of the way.
-Hubcaps off.
-Shell gasoline.
-Used Techron fuel additive 12oz. a tank before this one (does work well, link at bottom).
-Oil change done about 200-300 miles before the trip.
-Tires were rotated about 100-200 miles before the trip.
-About 15K miles on the vehicle.
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I'm not sure what else to include, I tried think of everything while I was driving to post here, but I may have forgot a couple of things. Anyways.. Just wanted to share my experience. I'm pleased with this car.
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I also had the average at 58.3 for quite some time until I hit a ton of steep and hilly terrain.
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Will report back on my way home in the next couple of days to see if I can pull the same numbers. Also, I was not driving like a grandpa, and was keeping up with traffic the majority of the time (I don't go 80 like some crazy people do)

Note: I realize this will be more like 55mpg calculated at the pump, however - I haven't seen these type of numbers on the prius with this type of driving before. Needless to say, I'm impressed.
Pic:

EDIT: Just got back from the second trip. No rain this time, same A/C usage, etc.. Got a little better mileage.

http://www.amazon.com/gp/product/B00092893O/ref=noref?ie=UTF8&s=automotive&psc=1

 

That's really good! The end of this trip is what killed me (when I really started to get into hilly terrain). No worries though, we're still getting better mpg than any conventional car would.

I don't believe that the fuel additive has anything to do with my mph either. I just wanted to include everything I've recently done to this vehicle along with how I drove and operated it throughout the trip so others could really compare every detail. According to the Amazon reviews, it sure seems like it may do wonders on older vehicles. However, I don't think it will do much in a Prius. I, although, do like to use a bottle of this every 10,000 miles. Using any top tier gasoline helps as well. I don't want to get into the fuel system cleaner debate. Just wanted to put that fine detail in there.

 

I wish I could get "ideal" conditions each time I went out on a drive. Oh well. Toyota could be doing that, but either way - the car gets great mileage and I couldn't be happier. It's not all about the mpg's for me. I love the looks, technology, low maintenance and everything else.:rockon:

 

Just an update. MFD shows 60.4 mpg on the way back. Calculated at 58.4. Not bad.
On the return trip, only a small traffic jam, and no rain - sunshine whole way. A/C ran the same.