The top 4 best-selling passenger cars are the Honda Accord and Civic, and the Toyota Camry and Corolla [1].
Their "combined city/highway" fuel efficiences are respectively 30, 34, 27, and 32 mpg for the base engine [2][3][4][5].
How can this possibly work out to 37 mpg overall? There aren't enough hybrid sales to bring that number up.
[1] http://www.goodcarbadcar.net/2018/08/july-2018-ytd-u-s-passe... [2] https://www.edmunds.com/honda/accord/2017/features-specs/ [3] https://www.edmunds.com/honda/civic/2017/features-specs/ [4] https://www.edmunds.com/toyota/camry/2017/features-specs/ [5] https://www.edmunds.com/toyota/corolla/2017/features-specs/
(Perhaps the mpgs were added up and divided by N? That doesn't always provide the answer you're looking for.)
> "skepticism" "It seems obvious"
Pick one please.
I am skeptical of the 37mpg claim because it seems clear to me that the average car sold in the US isn't that efficient. What's the contradiction?
As far as I can tell taking a quick look at your links, the difference can be in two things. First, these are fuel economy standards companies are expected to hit, and not reporting on whether they hit them or missed and paid penalties. Second there's the phrase "Assumes manufacturers fully use low-GWP A/C refrigerants credits". Apparently fuel economy numbers are boosted by these credits--actual fuel economy isn't the same thing, it appears?
(EDIT: Overall fuel economy for cars and trucks combined was 24.8 mpg in MY2015 [1])
[1] https://phys.org/news/2016-11-average-fuel-economy-high-mpg....