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

  1. i think you just need to count lanes. 401 has an insane number of lanes (maximum at one point and extended distance)… asia has some LOL traffic stories. i realize article is NA

  2. i agree……… toronto drivers are very fast on highway. i was thinking QEW. fast drivers are much rarer in vancouver (our drivers have other problems, like running red lights)

  3. People in Calgary complain about Crowchild Trail and The Deerfoot Trail. They have no idea what real traffic is…

  4. Given that I live in Ontario, North of Toronto, I have had lots of opportunities to drive the 401 (including one unpleasant day when it was dead stopped for most of it’s 500+ mile length from the Quebec border, all the way to Detroit). There have been occasions in the winter, when the police simply have to close off sections between Toronto and London, ON because of too much snow and it takes days to rescue all of the stranded motorists….

  5. Moved to Barrie, Ontario from the US. Not only is th highway system there inadequate, people on the highways (including the 401 and QEW are rude and ruthless

  6. Acknowledging that the 401 serves a significant goods movement function, from a people moving perspective, I think it’s important to point out that the Line 1 subway in Toronto carries almost double the number of people (790,000) on an average weekday. From a physical space perspective, look at the 16+ lanes with the grand interchanges on the 401 and then compare it to the the narrow two-track right-of-way of Line 1 (image below looking south to Rosedale station — I zipped back the years on google streetview and struggled to find an image with a train in it) and compact stations nestled into the neighbourhood or existing buildings.

    Beyond the footprint of the infrastructure itself:
    Subway: people access the stations mostly on foot contributing to vibrant, interesting, and walkable neighbourhoods around the stations that encourage people to talk and spend time. Pedestrians bring just themselves and what they can carry.
    Highway 401: Every person travelling along that corridor brings along a 2+ ton, ~2m x 4m vehicle. The result is a high demand for parking, especially around highway accesses but also the surrounding residential areas. Houses and businesses are consequently spaced far apart with a lot of asphalt in between. These in-between spaces are the last place anyone would want to linger or make spontaneous social connections.

  7. I’ve driven the entire length of the 401.

  8. Frankly, I fail to see this as a positive. How in the world is having the continent’s largest traffic jam a good thing? American large cities always have alternate expressways serving specific neighborhoods and communities. It would be very rare to see any city want to cram everyone on the very same artery. Urban bypasses are routine on the Interstate system.

Leave a Reply