Reaching 60 mph, fairly fast moving traffic and around 40-45 F. I also always engage the adaptive cruise control.
Note that the cruise control isn't usually the best way to high MPG. I use it all the time for convenience and safety in traffic. But, when I try to use good MPG driving techniques, I usually beat the cruise control.
Yeah, the cruise control will pull the mileage down, as will using Power Mode and even Normal Mode in comparison to the Eco Mode setting.
With the RADAR Cruise - I think it depends on the road. If it's fairly flat ground, I suspect the RADAR is better and more consistent than my foot in maintaining speed. If it's hilly, and there's no traffic around, I'll tend to slow off a bit going up hills and let gravy take it back up to speed down the next hill, maybe saving a nano-litre of fuel each time. You didn't say about whether your commute is short or long. A short commute always uses more fuel than a long one. I drove 120km a few weeks ago - after 2-3km the readout was showing about 7.5 l/100km, after about 10-15km; about 4.5 l/100km; after 120km, 3.3 l/100km.
That mileage seems low to me... I was getting low to mid 50 mpgs right from the get-go last September with ambient temps in the 50s-60s and summer tires. Do you have a lot of hill driving on your commute? I also wonder whether that mileage is what the car is telling you, on the trip meter, or whether you figured it out per tankful on paper (heaven forbid!). Watch whether you use the Trip meter A, Trip B, or from current trip, or miles to empty, or.... The trip button on the steering wheel cycles through 4 (or more) options.
Sounds about right. Cold temps, highway driving - both things that are not advantageous to a hybrid. I see the location is Seattle, so I assume the terrain isn't flat, either Your mileage will increase as the temps rise. Probably into the low 50s once temps are consistently above 60 degrees. As others mentioned, good human driving beats cruise control in many situations.
No one is mentioning it, but in Seattle he may have rain. It takes power to throw up all that spray behind your car, power that could have been better MPG. It takes more power to squeeze all that water out from under the tires. I am sure it takes a tiny bit of power to make rain falling down suddenly go sideways at the speed of your car.
... so wind-resistance becomes rain-resistance - which has to be greater. You're right with the tyres too - hit a patch of water on the road even a couple of millimetres deep and you feel the car slow. It can also affect traction on steep hills, wasting power with wheel spin. Good tyres should minimise this, but I remember driving my mother-in-law's car which she rarely used, the tyres were 10 yrs old but had only done 10,000km. Going up a steep, very wet hill on the highway at 80km/hr, the tacho started flaring up about another 1000rpm, ease off it got traction again, foot down again it would flare again. I had new tyres on her car the next day, but never was in that situation again to re-test it.
I figure I need at least 6 or 8 fillups to really get a good calculation, given the difficulty in getting consistant fillups, and the high fuel efficuency, where a small difference in the amount of fuel added makes a big difference in mpg, km/liter, etc. As far as actual economy, I averaged about 47 mpg for my first 5K miles. But I "just drive it," including 75-80 on the interstate. If you drive fast, like 75+ on the freeway, you will get "only" 46 or so mpg. I'm not complaining. Posted via the PriusChat mobile app.
This is the best I ever got. The car was only about 6 months old then. All city driving, crawling along at 35 mph in the early morning hours with no traffic. It was just a test. 68 mpg in PWR mode. I never tried that again. Totally unrealistic. Just for fun. Now days, 2 years later, I just drive the car normally. In Eco or Normal mode. After going 600 miles, the mpg calculates to 56.5 mpg. And that's all city driving with the AC always on. I can't complain about that! (And I never drive more than 600 mi without refueling.)
