Deceleration for the nation!

The question is, would I be allowed to use the road instead, if I go anywhere between 45kph to 60kph, as I tend to do on road-/gravelbikes on flat grounds, without too much head wind?

Thinking about it I even do 45kph with an old 3-speed rear hub and coaster brake, mudguards, dynamo, porter, basket, from 1985 when in Hamburg.

This makes no sense for me. Maybe don't declare bike lanes as such, if they are unfit for the purpose?