Trucks hitting 70 downhil

[T5R+]

Recently had a spell on the M1 (in the car) and whilst following trucks downhill, couple of times noticed that they were nudging 70 (GPS not speedo verified). Happened three or 4 times over the week.

Is this still normal?

Admittedly on on 2 occasions they were machinery movers complete with hiabs but on others conventional tractor+trailer.