With all that said, it's hardly a surprise that the prius is fairly efficient on the highway. It's got a tiny little anemic engine. You can do a lot when you don't request a lot of power from a small engine. How acceptable this is depends on your driving style. If you drive a prius at 55 mph in the right lane, you will get far better mileage than if you go 80 in the left. This is of course true for gasoline as well, but the difference is that many prius owners specifically want high mileage and others specifically don't want to be associated with the former group. The car is polarizing, politicized, and this makes getting good information harder!
Interesting. I'm typically driving on Cleveland interstates where I top out at around 70 MPH; on road trips I might get to 80 depending on where I go. At those higher speeds, would a plain gas engine overtake a Prius-style hybrid in fuel efficiency? Edit: I wonder if there's a source for fuel efficiency numbers at a given speed; that would let me get a much more accurate picture of how efficient cars will be with my usage.
I'm not particularly attached to one car or the other and I'm definitely looking at everything reasonable in our price range.
This could all be moot since I currently drive a 2003 Impala (inherited, I didn't choose this one). I may hate the Prius when I test drive it! Everything's just on paper right now.
That data definitely exists, for example, this company -
https://www.automatic.com/ - sells a doodad that you plug into an ODB2 port and it tracks your mileage and speed (among other things) and gives you a nice graph of your mpg vs speed.
But where's the data?
Here's bullshit -
http://www.mpgforspeed.com/ - they don't care what car you drive, just your rated mpg and speed. That is on its face utter bullshit; cars that are more aerodynamic lose less at high speeds. It is blatantly obvious it's not this simple.
But how about automatic's blog?
http://blog.automatic.com/cost-speeding-save-little-time-spend-lot-money/ this includes "the" prius, but again, there are different models. Good start, but I want raw data!
The company should have a treasure trove of data, for every conceivable model and multiple samples of each model, assuming they're doing okay and selling enough product. (By the way, it's not exactly a "mustachian" purchase at $80, but it's a fun toy. And you could turn it into an investment by using it to find out how to drive more efficiently. They're a startup, with cool people working there.) However they don't seem to publish this information anywhere!
TLDR data exists, I can't find it, sorry.
Also, their math is not entirely honest - they compare minutes saved per hour versus cost of gas per month. Different units. Compare time saved per month of driving or costs of gas per hour. With that said, it is indeed true that for most drives, driving aggressively will save you about one minute and cost you a dollar or two of gas (not to mention the damage you're doing to your brakes, the wear on your engine, the hits to your suspension when you miss the pothole or speed bump), so chill out and don't hurry too much. But when it comes to long distance travel, that extra time adds up really quickly - I tend to go +7 in a 65 and over a day's drive that's over a hundred miles more that I can go. Worth it to me.
70-80 mph up this big hill is pretty good for an "anemic" engine
It is pretty good for that anemic engine. Heck, even flooring it, you get better mileage than I do! With that said, I've been there, and my car on cruise control at 80 needs 2300 RPM instead of the usual 2100 to make it up the biggest mountains the interstates go through. So no need to put sarcastiquotes around "anemic," it is very anemic, and there's nothing wrong with that as long as you stay out of the left lane when you're not passing, which is the only time I take issue with anemic engines. Though I must wonder at the wear you put on the car at 4500 rpm, or however fast the engine has to spin to maintain speed. How long do those engines generally last for? (My car will fall apart long before my engine is even a quarter through its life, which is a bit sad about the rest of the car. GM, why couldn't you do better?)