That’s because the CAFE figures are based on the original city and highway fuel-economy tests established in the Seventies, while the window-sticker numbers combine those values, along with the ...

35.5 mpg doesn't REALLY mean 35.5 mpg Most folks confuse CAFE numbers with the gas mileage they get, or what's promised on the window sticker, which these days seems pretty far away from 35 mpg.

Taking the CAFE mandate and adjusting it to compare to fuel-economy numbers you'll actually see on window stickers brings the target closer to 40 mpg.

When consumers complained that the number didn't correspond to real-world gas mileage, the EPA determination formula was changed – twice – yet the CAFE formula wasn't.