Wondered about my Prius mileage but then

Aero drag is a bitch. Engineers have done what can be done with 0.25 Cd.

See the table below. There is one thing the driver (you) can do.

	Column 1
0	MPH Watt hours per mile % of Energy used to Overcome Aerodynamic Drag
1	40 152.8 Wh 29.8%
2	45 181.3 Wh 31.9%
3	50 190.8 Wh 37.3%
4	55 202.9 Wh 42.5%
5	60 215.5 Wh 47.6%
6	65 233.4 Wh 51.6%
7	70 250.3 Wh 55.8%
8	75 268.5 Wh 59.7%
9	80 287.8 Wh 63.4%

Source

 

Yay! Those are great numbers. I've never seen anything that high on my 2nd gen.

Aside from the claims/reported mileage by people here, if had expectations based upon EPA estimates, http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html is good reading, if you haven't read it yet.

 

How and where you drive can have a HUGE impact. In the 7 years I have owned my car, I have, unfortunately had several jobs with widely varying routes. My mileage has changed greatly.
1) for the 1st 4.5 years I owned the car, my commute was 25 miles each way, usually in moderate to heavy traffic. Got 45-50 in winter, and 50-55 in summer.
2) then a 40 mile commute for 4 months, almost all highway, but off times, so not much traffic. 50 MPG
3) then 8 mile commute for 10 months, depending on route, was about half highway or no highway, mid to high 30's
4) now 30 miles, mid 40's, for the last 4 months, but just found out my catalytic converter is bad, so that maybe dragging it down

 

Wondering if any drafting occured which resulted in + mpgs.

 

In addition to dramatic improvement in fuel economy, slowing down can also help moderate your blood pressure and can provide the opportunity to "smell the roses."

 

Yep. My lifetime average when I had a much longer commute in CA, about 2/3 of it by time on the highway was ~46 mpg.

Now w/my colder climate, very short city drives and a bunch of uphill to start (and downhill that frequently causess my HV battery to get "full" (to 77+% SoC that the ICE starts up), I'm lucky to even get 40 mpg.

 

I think you figuired it all out. I drive alot in charlotte, I 77 speed limit is 55 so i go 55 to 65 with traffic. And i get some city driving in there too. At the high speeds your driving i would get in the mid 40's. i get over 50mpg going a max of 65, bot alot of 55-35 mph driving thats gets me 50-54mpg.

 

Not for me, no. Hate being behind a vehicle I cant' see thru. Not worth 3 MPG to me to try to stay in behind a truck or close enough to a car to get the drafting effect at the possible expense of rear ending someone.

 

+1, or try to dodge a blown tire if your drafting a large truck.

 

Even staying a few car lengths back really results in a boost, so I think your results still show the effects of drafting.

You aren't drafting like a NASCAR driver does with less than a car length, but even at 10-15 car lengths you can notice the effects.

Here are the results of the Mythbusters test.

Reduction in fuel consumption driving behind a semi trailer at 55 mph, per distance trailed

100 ft (30 m) 11%
50 ft (15 m) 20%
20 ft (6 m) 27%
10 ft (3 m) 39%
2 ft (1 m) 28%

 

The Prius is just under 15 feet long so:

100 ft (30 m) 11% is 6-7 lengths back
50 ft (15 m) 20% is about 3 lengths back
20 ft (6 m) 27% is about 1 length back
10 ft (3 m) 39% is 2/3 length back
2 ft (1 m) 28% is 1/7 length back

IOW, closer than you would think.

Incidentally, 100 feet is a tad over 1 second at 60mph (88fps), less than that at higher speeds. Good reflexes?? Basically, if you are drafting at a distance close enough to have a significant draft effect you are dangerously close. If you are at a safe distance, there is very little effect.

I tried drafting a truck once and discovered that any sort of terrain strategy was impossible, and constantly reacting to what the truck was doing meant that I couldn't drive efficiently.

I found that I could do a lot better mpg wise by NOT drafting trucks: 67.7mpg on the display today over 140 miles from Boston to here, a good part of it with the AC on set at 75 degrees. Figure 3-6% less when corrected for the display error.

 

Actually, well back is almost as good. Trying to stay too close can adversely affect mileage is you have to speed up and slow down to keep your gap. But staying back you were probably still in dirty air, so got some benefit - unless it was more than a 100 yards or so.

 

Did run into a piece of sheetrock a couple of weeks ago, like 3' x 4' left nasty scrapes in my hood.