Quebec Autoroute 15

Southern section

The southern section of A-15 connects the south shore suburbs of Montreal and is also the primary trade corridor route between Montreal & New York City linking Quebec Autoroute 15 to Interstate 87 at the Canada-United States border at the Champlain-St. Bernard de Lacolle Border Crossing. This was the former Route 9, and connected with US 9 on the western shore of Lake Champlain. In Brossard, it joins up with A-10 and A-20 across the Champlain Bridge into Montreal. The A-10 splits off almost immediately after crossing the bridge to head into downtown Montreal at the Bonaventure Expressway and the A-20 splits off shortly after at the Turcot Interchange (échangeur Turcot), leaving the A-15 to continue northward as Autoroute Décarie until the Décarie Interchange (échangeur Décarie) with the A-40 at the point where it turns from the Trans-Canada into the Metropolitan Expressway.

The route is also connected to Autoroute 30 in Candiac which was completed to Autoroute 20 in 2012 providing a quicker access to the south shore of Montreal, to southern communities located alongside Autoroute 15 and to the Canada–US border in Lacolle. It will also give a quicker access from there to areas west of Montreal and also Ottawa and Gatineau.

Autoroute Décarie

The Autoroute Décarie is a sunken highway between the northbound and southbound lanes of Décarie Boulevard (hence the name); from boulevard Métropolitain at its northern end to Monkland Avenue and the Villa Maria Metro station at its southern end. It was built on a wide expanse of vacant land, donated to the City by the Décarie estate on the condition that only a streetcar line be established. The decommissioning of the streetcar system in 1959 left the right-of-way as an obvious choice for a highway, and so the Décarie Autoroute was dug there. South of Queen Mary Road, however, were a significant number of houses that were demolished. In order to avoid demolishing the Notre-Dame-de-Grâces church, the highway makes a slight westerly jog below Côte-Saint-Luc Road and runs through a short tunnel, before emerging between Addington and Botrel Streets and running down to Sherbrooke Street and Saint Jacques Street, where it spectacularly goes from below-ground to well above ground as it intersects with Autoroutes 20 and 720 in the infamous Turcot Interchange (dubbed "Spaghetti Junction" by train crews operating the former CN Rail Turcot Yard). Following the conversion from streetcar line to highway, the Décarie Estate unsuccessfully sued the city but was unable to prevail because they did not document their case well enough for the nevertheless sympathetic court.

Decarie Boulevard itself continues; from Monkland Avenue south to Saint Jacques Street and McGill University Health Centre Glen Campus superhospital; and from Autoroute 40 north into Ville Saint-Laurent past Du College Station and Côte-Vertu Station/Norgate shopping centre.

Northern section

After its concurrency with A-40, the northern section of A-15 is the main freeway route to the Laurentians until it downgrades to Route 117. It also links up to the northern suburbs of Montreal, as well as provides a connection to the A-440, A-640 and the A-50 in Mirabel. The first section from A-40 to Saint-Jérôme was opened in 1958 as a toll road, although the tolls were removed in 1985. This section was also the first to be designed as an autoroute in the province. It was named Autoroute Montréal-Laurentides during the 1960s.

Over the next years, it was extended north to Sainte-Agathe-des-Monts as a new connection to touristic and skiing destinations in the Laurentides including in Saint-Sauveur, Sainte-Adèle, Mont-Gabriel and Estérel. In the future, it is possible that the A-15 may continue even farther north, past Mont-Tremblant, as Route 117 is already an at-grade expressway with a freeway bypass of Saint-Jovite completed, and the name Autoroute des Laurentides is also recognized on the freeway bypass (and exit numbers continue). This section is numbered separately from the southern section as if it were a different route. The northern route is also part of the Trans-Canada Highway.

Exit list

Exit numbering resets at the two interchanges with Autoroute 40 in Montréal.

Disasters

On June 18, 2000, the southern portion of the Boulevard du Souvenir overpass in Laval, which crosses Quebec Autoroute 15, collapsed into the roadway, killing one and injuring two when cars were crushed underneath the structure. Sixteen beams weighing about 70 tons each fell. The contractor was faulted for shoddy work.

The expressway has also seen flooding. On July 14, 1987, a sudden torrential downpour caused by an HP supercell thunderstorm dumped over 100 millimetres (4 inches) of rain in just over one hour across the city. The Décarie Expressway, which is below-grade, was heavily flooded and became a river. At some locations, the water reached a maximum of 3.6 metres in depth on the roadway. Over 300 vehicles were abandoned when they were submerged. Two people were killed by the storm. One 80-year-old man on the Expressway drowned and another one was killed by electrical wires. On July 5, 2005, another torrential downpour flooded portions of the Expressway after several manhole covers blew open from the storm sewers below them being overloaded.