Toyota wasn't BS'ing !

Toyota SELLS Priuses based on their fuel efficiency, so it's no surprise that they will at least attain something close to the EPA guestimate.

However (COMMA!!!!) beware that Toyota has famously put their thumb on the scale when self-reporting their car's efficiency in the past.
I would take the number that the car provides you with a side-order of skepticism until I measured real-world efficiency with a Mk-1, Mod-0 eyeball looking at an odometer and a fuel pump, rather than what the car says.

I'd like to think that by now, Toyota has outgrown their 3-4% .....um......"error" in MFD reported mileage, buuuut......

 

I took a road trip to Prescott AZ (about 350 miles one way) including mountain roads. On the way there, I took it slow with cruse set at 65, had a tail wind though San Gorgonio Pass and went up the mountain. No electric miles. I got 68 MPG, real gas pump number. On the way back down the mountain i was ready to be home, driving aggressively and doing 80-85 (flow of traffic) and against the headwind in the pass, i got 55 MPG. I freaking love this car!

 

its not the manufacturers, its the epa. they have a standard test, and some cars are more difficult in real life than others.
otoh, check toyotas dash readout vs manual pump calculation if you want a reality check.

of course, ymmv

 

First of all, Congrats on your new Prius and successfully braking it in. I am sure it will continues to impress your for it's efficiency as I have on my now 3 years old Prius Prime.

Just a few words of caution here. Is this 56.6mpg read from the display on the car? If so, it is bit optimistic. The real mpg by hand calculating method (gas fill-up to next fill-up) is likely to give you 5-7% lower number than that. If that is the case, your real mpg is likely to be ~52-54 mpg which is very close to published EPA estimate.

Years ago, that may have been allowed, but I think EPA testing is now regulated. Manufactures can not overestimate the fuel efficiency any more??? Honda did that some times ago, and got in a huge classification lawsuit. Now, almost all the manufactures are very cautious overestimating the fuel efficiency and it always includes YMMV disclaimer in the advertisement.

 

Sorry.
Military slang meaning First version, unmodified.

Think:
"Old School."

As noted above....
YMMV.

 

correct, although, there have been a few outliers

 

Yup, around 7.5% "rose tinting", in my experience.



That last tank is pretty abysmal. Ah, a lot of short trips, on 17" #$%! Michelin Primacy's. It'll get better. I don't care...

 

It will be ymmv

why, because maybe you are using cruise control, maybe some wont
maybe some drivers drive like foot on floor, full gas/full brake.

Take averages of foot stompers and hypermilers and maybe drive "normal" and get EPA or better

 

My error factor for both my 2008 with 120,000 miles and my 2016 with 43,000 miles is almost exactly 5% overstated.

 

That shortfall on the other cars was likely a California speed-limit-be-damned thing. I've probably been driving longer than you, in mostly lower speed areas, and have had only a single car fall short of its EPA sticker. Initially. But that was remedied by learning more about how to drive for efficiency, boosting my results well above the Monroney/EPA window sticker.

Because the other car makers that did that and got caught, were sued by the government, forced to re-test and re-score their cars with EPA regulators watching, and give fuel credits to buyers who bought based on the earlier fictitious ratings.

Those rating tests are defined by the EPA, and it is illegal for car makers to advertise or display any other MPG figures.

 

Loath to open a can-o-worms, but the tests are done with ethanol-free gas, which improves mpg maybe 3%.

 

It doesn't actually matter what fuel blend they use for testing, the amount going into the engine isn't even directly measured. At least in the U.S.

Instead, the tests measure tailpipe emissions (CO2, CO, HCs), then use an EPA formula to compute backwards to some standardized fuel blend. This may well be an E0 blend, not E10. But it doesn't matter much anymore, because other factors have caused a lot more shrinkage than the mere 3% E0-E10 difference.

Over my decades of driving, the EPA scale has been adjusted numerous times, adding more tests and always shrinking the final advertised MPG "score". This reflects changing driving cultures: faster highway speeds, increased congestion, more aggressive accelerations (enabled by horsepower wars), and increased A/C use (now that most everyone has it). All these increase fuel use, so that the CAFE scores originally used for EPA ratings (and not very close to real word even then) are no longer relevant for most people.

The old CAFE numbers are still used to keep a stable yardstick for the increasing fleet mpg laws, but cannot be used in car advertising. For those who must know, the 2020 Prius has CAFE scores of 76.4 mpg City, 70.0 mpg Hiway, on conventional fuel. The full industry datafiles can be found here: Download Fuel Economy Data

 

I remember a few years back, someone pulled up at a house across the street, and I think someone hopped out and went into the house. Maybe a music lesson situation? Anyway, driver stayed in the car, engine running, for a solid half-hour, at least. And AC apparently on, cus you could hear the fans roar on, every 20 seconds or so, then off for about 20 seconds. On and on, and it wasn't even really a hot day...

At the time I thought "this person is a near-unique case". But nope, now: I see so many people, in their little enviro-bubbles, engines and fans whirring away.

 

As I've said before - it's not just TOYOTA's dash readout - they're all the same. Go on any of their brand/model specific blog, and it's mentioned in almost every case.

Try GOOGLing "dash readout vs manual pump mpg difference" - and you'll get nearly 3 million hits.

 

Then I've likely countered before: our 06 Civic Hybrid (first car for us that displayed fuel economy) was either spot-on or one tenth (of a liter per 100 km) on the pessimistic side. For example if calculated was 5.0, the displayed would also be 5.0, or sometimes 5.1 (worse).

I'm not sure if they've kept that up though; they mighta joined "the herd".

 

E0 can be a little harder to find out on the left coast.
My own efficiency gains were 1-2% back when I measured such things.

Not very “efficient” given the price, especially in a state where people will wait 20 minutes in line at a Costco to save a few centavos on fuel.