Unlike the Interstate Highway System in the United States, the Trans-Canada Highway system has no national construction standard, and was originally built mostly as a two-lane highway with few freeway sections, similar to the United States Numbered Highway System. As a result, highway construction standards vary considerably among provinces and cities. In much of British Columbia, Ontario, and throughout Prince Edward Island and Newfoundland and Labrador, the Trans-Canada Highway system is still in its original two-lane state. Other provinces have twinned the vast majority of their portions of the Trans-Canada Highway system, and in the case of Alberta and Saskatchewan, their entire segments of Highway 1 to a four-lane divided highway, albeit with at-grade intersections in most areas. British Columbia is actively working on converting its section of Highway 1 east of Kamloops to a four-lane route.