When I lived in Calgary, there was a 20 kph speed limit on the pathways and the police would go out once or twice a year and ticket cyclists who went over it. Since 20 kph (13 mph) is what a reasonably fit rider can do going uphill into a headwind on a road bike, there was little incentive for serious riders to use the pathway system. Not to mention the hassle of constantly having to pull out and pass people. Groups of gossiping walkers were the worst, they didn't see any good reason not to spread out and take up the whole path.