In 1975, I elected to violate the restrictions on "Going to the Sun Road" in Glacier National Park. Interestingly enough, it it still prohibited:
"From Logan Creek to Logan Pass east-bound (uphill) bicycle traffic is prohibited between 11 am and 4 pm."
This is/was a major impediment, so I went ahead. I made it through without being stopped. But, then I ran into this:
"From Apgar Campground to Sprague Creek Campground bicycles are prohibited, both directions, between 11 am and 4 pm."
And yep, I was pulled over. I told the officer that I thought it was unreasonable. He offered to write me a ticket so I could contest it, but I decided to stay off the road until 4 p.m. (Actually, I think I started off again at 3:30 ...).
45 years later, I still consider these restrictions to be unreasonable. I think the main reason they exist is that so many "recreational vehicles" are on the road and the inexperience drivers could/would crush you into a wall.