Mixed use trails have a serious operational problem: mixing three types of traffic moving at very different speeds.
The hiker, traveling “shanks mare,” moves pretty slowly. They may be heavily laden with pack, sleeping bag, etc. They can lack visibility and are not very manueverable. They don’t generate periodic, large waste deposits.
The horseman moves faster (even at a walk). While he may be capable of higher speeds he generally is at the low end of the range. Can be carrying a heavy load, but even if he is remains fairly manueverable. Has excellent visability. Does leave periodic, large waste deposits.
The biker moves faster than either the hiker or rider almost all the time (a possible exception being long climbs). He is generally not carrying a big load (although he could be). His visibility is good, manueverability good, but due to speed can have a limited time to react to a sudden obsticle. Does not leave periodic, large waste deposits.
Waste generation is a frequent complaint of hikers and bikers.
These three very different “ways of going” are not going to mix well unless and until each recognizes the limitations of the others and plans accordingly.
G.