In most of Western Canada, an expressway is a high-speed arterial road along the lines of the California definition, while a freeway is fully controlled access with no at-grade intersections. In Alberta, the term "Trail" refers to both full freeways (Stoney Trail), or high-speed arterials with a mix of signalized intersections and interchanges (Crowchild Trail). The Yellowhead Trail as it passes through Edmonton, Alberta has both intersections and interchanges. It is the main east-west artery for the northern half of the city. There are plans to upgrade many of the most congested remaining intersections into interchanges in the near future.