The new Fords will apply the brake when using adaptive cruise control and you come up on an object that is going slower. It also applies the trailer brakes.
I went back and compared this run to the F-450 run with 30,000 lbs. Figured with the gearing equaled out by the tire size should be about the same. Looking at the videos the F-450 was in 3rd running 40 MPH around 2600 RPM(video at 8:44 mark). The F-350 was runnning in 3rd at 40 MPH around 2600 RPM(video at 12:13 mark). Both of these occured near the bottom of the climb by odometer. The F-450 held these figures for the whole climb(10:29 mark past 7 miles) while the F-350 dropped down to 2200 RPM's and around 36 MPH(13:09 mark past 7 miles). I wonder why the F-350 dropped off in RPM's while the F-450 could hold them with the gearing being effectively equal and the less weight on the F-350? The F-450 run was 20 seconds quicker than the F-350, but they said it was stopped early for traffic, so don't know how it compares to the stopping point for the F-350.
F-450 Ike