Bus travel can
be slow compared to the subway, since heavy traffic limits the average
speed of a city bus to about nine kilometres per hour. Dedicated bus lanes
within the city help buses to remain on time, but for pure speed, the bus
still remains far behind the Métro. The main advantage of a bus for visi-
tors is that it is considerably more scenic than the Métro, given that buses
trundle about on city streets, whereas subway trains spend almost all their
time in tunnels.