<P> White - on - green Trans - Canada highway markers are used on King's (and 400 - series) Highways designated as the national route, and are posted below the standard provincial marker . </P> <P> The speed limit on King's Highways is generally 80 km / h (50 mph) in rural areas and 50 km / h (31 mph) in urban areas . On rural portions of the Trans - Canada Highway, on RIRO and at - grade expressways, and on certain other highways in Northern Ontario, the speed limit is 90 km / h (56 mph). </P> <P> 400 - series highways are a special class of provincial highways, designed to be exclusively controlled - access freeways for the entire length of the highway . At present, all of them are located in Southern Ontario, where they form a network similar to the Interstate Highway System in the US . The 400 - series highways include Highways 400, 401, 402, 403, 404, 405, 406, 407, 409, 410, 412, 416, 417, 420, 427, and the Queen Elizabeth Way (QEW). Originally, 400 - series route numbers were assigned sequentially, but more recently new routes have been numbered based on the existing highway the new route bypassed or upgraded . (Highway 427 is an upgrade of Highway 27, for example .) </P> <P> Although the province also maintains freeways that match 400 - series standards, such as the Conestoga Parkway, they are not designated with a 400 - series number, even though some of those freeways exceed some existing 400 - series highways in size and traffic volume and are in some cases connected to the 400 - series network . Nonetheless, Ontario freeways do not receive a 400 - series number unless they are designed to be complete controlled - access freeways for their whole length . While at - grade intersections existed on Highway 406 for many years, construction took place from 2008 to 2015 to close off intersections or replace them with overpasses and interchanges, bringing the route to full freeway standards . The non 400 - series routes typically have open - access portions besides the freeway section, while the freeway segment is typically a small section not at the route's termini. 400 - series standards do allow for 400 - series highways to begin or end at roundabouts or traffic lights, such as Highway 406 and Highway 420, respectively . </P>

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