EPA estimates avg speed
 

my car's EPA mileage estimates are 20/26 MPG (22 combined). getting about 23 mpg at avg speed of 26 mph last tank. How does EPA estimate how much % city or highway this is? thanks.

There is information on the EPA site. Check the PDF that is first on the list at the botton subhead "related information". A claim there is that the ratings are 55% city and 45% highway. They test indoors. Data & Testing | Fuel Economy | US EPA

Yeah, they essentially hook the vehicle up to a fancy dyno, run it according to a given test procedure which specifies accelerating, cruising, stopping, all on a specific timescale, and under fairly stringent environmental settings. I don't think it's a terribly realistic test procedure (since it cuts out real-world aerodynamic benefits by only simulating aero loading on the dyno). Thankfully it's not meant to be realistic, but it IS a repeatable measure which shows how different vehicles perform under different standardized tests, which is helpful for comparing vehicles.

Except they often used specs from manufacturers without confirming them, and it seems they often don't do the testing.

Actually, EPA periodically DOES "pull" a new vehicle from a manufacturer and performs their OWN tests, but that's typically ONLY done AFTER customers have complained about the MPG numbers...numbers that the EPA "rubberstamped" after receiving them from the manufacturer.

thanks I still couldnt find out the avg speed numbers. However I did read that 48mph is 100% highway somewhere for EPA. still not sure about city. I think in europe someone told me 23mph is considered 100% city?

So less vehicles than I estimated. :confused:

For all the money we (our government)[waste], I fail to understand why they don't mandate all vehicles run a test under their conditions- an entirely "fair" system, and use those numbers.

Yes, lots of that seems to be going around.

Detailed Test Information

There's the test info for the different schedules. City average is around 21 (although has a max of 56), Highway average is 48 with a max of around 60. I'm not entirely sure what you mean by "100% highway" and "100% city", but I think you're trying to indicate that at these speeds a vehicle will attain their EPA estimates, and that's just not accurate. These are tests which are supposed to mimic the types of driving which people do: a 30 min trip on city streets with many stops and some medium speed segments, a 12 min trip completely on the highway at reasonably high speeds, a 9 minute trip at high speeds with several starts and stops, a high-speed high variance test with the AC cranked, and a repeat of the city test in the cold.

Where I live highway means getting up to 65-80 and holding it there until you need to pee or run out of gas. I'd love to see the ratings of what car does that the best. Then in my "city" you never get over 45 and mostly driver around 30 mph.