Just where is the busiest freeway in North America?

While the United States may have the largest road network in the world, the title of the busiest freeway on the continent belongs to their neighbors up north in Canada with its Ontario Highway 401.

Known as King’s Highway 401, the freeway also goes by its official name of the Macdonald–Cartier Freeway. A 400-Series Highway in the Canadian province of Ontario, the 401 stretches from Windsor to the Quebec border. The segment of Highway 401 passing through Toronto is not only the busiest highway in North America but also one of the widest and busiest in the world.

So, what makes this freeway so busy? According to a report from the Federal Highway Administration, the annual average daily traffic (AADT) count between Weston Road and Highway 400 in Toronto was estimated at 431,900. On some days, the number exceeds 500,000 vehicles.

Those stats make the 401 the the busiest roadway in North America, surpassing those in the U.S., including the Santa Monica Freeway in Los Angeles, Interstate 10 (I-10) in Houston, and I-75 in Atlanta.

Have you driven on Ontario Highway 401? What was your experience like? Be sure to let us know in the comments below.

Image: Danielle Scott, PLTam

  • Stacey Rocheleau-Bourgeois

    It’s horrible. I hate crossing Toronto because you never know what you’re going to get.

  • Mr. Khayat

    I just moved (and drove) from Albuquerque to Montreal for college, and I can honestly say the worst traffic I’ve ever seen, including Bangkok and LA, was the 401 in Toronto. I almost had a heart attack and saw TWO pileups caused by people passing on the right and swerving back into the fast lane.

  • Toronto My Way

    Population yes, but geographical area?

  • Toronto My Way

    Except that the 401 doesn’t touch the vast majority of the province of Ontario. The stretch it does borders 4 states along Lakes Ontario and Erie.

  • Michael Scott

    Did you mean to say “OUR” government?
    401 less busy in London? Duh.

  • Michael Scott

    Be careful when you say “much bigger cities”…..you might be misleading.
    The GTA alone is FIVE TIMES the size of NYC. Not to mention, if you’re traveling through NYC, you’re going from nowhere to nowhere. If you’re traveling through Toronto, you could be just crossing town…..or on a 300-500 mile trip across a province that’s 8 times the size of New York State!

  • Michael Scott

    I agree with you about selling out the 407…….but, you’re forgetting a couple of EXTRA ways to get from Mississauga to Toronto: QEW……and Lakeshore Blvd. Oh……and Dundas St. (Hwy 5)…….and I’m sure a couple of others we just don’t think about…..because we always think about 401/407.