Saying that they are designed for bike traffic, when they are continuously rebuilt to the needs of motorised vehicles, is a bit like complaining that it is problematic marching a centuria down the middle of the A59 out of York, given that is what the Romans designed it for.

And we do have a solution to this problem, it is that of creating dedicated bike routes, like the Bristol to Bath cycle path, or where they have to run alongside roads with cars doing 60mph and above, keeping them separated by more than just paint.