It is not uncommon to see a whole pack of police cars lined up there. It may happen at any time of the day, they are just there to radar anyone who drives or rides above the unrealistically low speed limit of 50 km/h. There is a slight uphill if you’re coming from the south and heading towards the Lachapelle bridge, so you might not see them until it is too late. They also radar you whenever you cross the bridge. Beware. Many of my friends have gotten heavy fines there.