The Toronto speed limit on multi-use trails is 20km/hr. To pedestrians, I would think this is pretty fast. A jogger is around 9 to 10 km/hr. A 100m sprinter in 10seconds is 36km/hr. So until a fatality does occur due to a bicycle going at 20km/hr this top speed will remain.
On the other hand, how many motorists obey the speed limit anyways?