The average STM bus moved at 17.7 kilometres per hour in 2016, but many transportation experts say that could be improved.
By comparison, Radio-Canada reports that buses in Quebec City average 21 kilometres per hour, while in Vancouver they roll at a relatively brisk 25 kilometres per hour.
The calculation takes into account several factors including the number of stops on a route, the time of day, traffic congestion and road construction and detours.
The STM says there are other factors to consider including the weather and the gradual reduction of speed limits in recent years in many cities and boroughs.
A spokesman for a transit users lobby group (Trajectoire Québec) says adding more express routes and implementing a policy of allowing the boarding of passengers through all doors would help improve service.
A professor in Urban Studies at the Université du Québec (Florence Junca-Adenot) says creating more reserved bus lanes and synchronizing traffic lights are two other methods that could be adopted.