Got my record best 35.5 mpg on a 3 hr road trip. 3 large adults with tons of Xmas stuff and luggage. It's been crazy foggy most mornings so my speed varied from 35-50mph for the first half of the trip then went up to 70-75mph. I have checked miles driven/gallons added in the past many times and my dash readout has always been spot on. 2017 RTS FWD, 38psi stock tires. Just got that high/low pitched ANC feedback above 70mph that comes and goes on this road trip for the first time but the gas mileage was amazing for a truck!