I'm glad you've backed off your original comment. The problem is not cyclists violating the posted speed limit or who "ignore() the law." The problem (at least one of many problems on MUP's) is cyclists riding too fast for conditions. Thoughtful speed limits can be useful, the city is just too lazy to put thoughtful limits in place.

I have a 35 mph, three-lane, one way street on my commute. There's a school on it, and during certain hours, a light flashes indicating that a 20 mph speed limit is in effect. Cars actually slow down because they know the limit has a purpose. If the city had just posted a 24/7 20 mph speed limit there, a few cars would slow down no matter when, but most would ignore it, even during school hours.

My point is that if you want a low speed limit to work, it has to make sense to drivers/riders. Traffic engineers generally get that when they work on streets, but bike path designers sometimes forget it.

True, but I can't find any law that makes speed limit signs on our MUP's anything more than suggestions. The parks director put up signs. Sometimes putting up signs is enough to turn a suggestion into a law. Sometimes not. But I haven't found anything that makes the signs on Columbus MUP's anything more than suggestions. Could the city pass an ordinance that would make the speed limits truly limits? Probably. I just don't think they have.

There's a very helpful internal door in my workplace that connects a couple of back areas. Some late-night security guard kept locking it using a non-key dead bolt on one side, which was a small nuissance when you were trying to use it during the day because it would add a few minutes to walk around and unlock it (I said it was a small nuissance). I used a label maker and put a tiny "Do Not Lock" sign by the lock. The guard must have assumed that whoever put up the sign had authority to do so, and it's never been locked since.

Just because someone puts up a sign, it doesn't mean they had authority to do so.