I do a fair bit of riding on MUPs in Ottawa Ontario, and my experience has been sometimes similar, but it depends on the time and day you are riding. Sunday afternoon is hair raising, but Monday morning is thousands of commuters travelling at a decent speed. However, they are 'multi-use-paths', and bicycles are generally expected to give the right-of-way to other trail users. If I want to ride fast or long distances, I ride on the road.