Ontario Highway 401

At the end of 1968, the Gananoque–Brockville section was bypassed and the final intersection grade-separated near Kingston, making Highway 401 a freeway for its entire 817.9 km (508.2 mi) length.

[7][11] The just-in-time auto parts delivery systems of the highly integrated automotive industry of Michigan and Ontario have contributed to the highway's status as the world's busiest truck route,[12] carrying 60 percent of vehicular trade between Canada and the US.

[1] The highway is one of the major backbones of a network in the Great Lakes region, connecting the populous Quebec City–Windsor corridor with Michigan, New York and central Ontario's cottage country.

[15] By September 2025, the Gordie Howe International Bridge will extend Highway 401 across the Canada–United States border to a connection through Delray to Interstate 75 in Michigan.

[18] Southwestern Ontario is flat, primarily agricultural land, that takes advantage of the fertile clay soil deposited throughout the region.

[42] The east end of this section, running south of Toronto Pearson International Airport, reaches the Highway's widest point, at 18 lanes.

This is also the west end of the third and longest express-collector segment (43.7 km (27.2 mi)) which crosses the rest of the city to Brock Road in Pickering in the east.

[44] The 5 km (3.1 mi) gap with no express/collector split between Highways 427 and 409 is a traffic bottleneck, since the space constraints of the existing flyovers of the at the 401-427 interchange also limit the width of the 401 in this section to eight lanes (widened from the original six).

[11][72] When widening in Scarborough reached the Highland Creek ravine in 1936, the Department of Highways began construction on a new bridge over the large valley, bypassing the former alignment around West Hill.

[11][75] Along with immense improvements to machinery and construction techniques over its six-year course, the war provided planners an opportunity to conduct a survey of 375,000 drivers, asking them about their preferred route to travel to their destination.

The reporter continued, with regard to the eastern section through Scarborough, that it "winds smoothly through pastures across streams and rivers, and beside green thickets.

[88] In 1958, a section bypassing Morrisburg was opened to accommodate traffic displaced from a portion of Highway 2 through The Lost Villages of the Saint Lawrence Seaway.

James Auld, MPP for Leeds and the Minister of Tourism and Information, joined local residents to persuade the DHO to construct an inland bypass.

[98] Despite the expected influx of traffic from the United States for Expo 67 in Montreal, the DHO opted to build the portion east of Ivy Lea after the centennial celebrations.

In 1963, transportation minister Charles MacNaughton announced the widening of Highway 401 in Toronto from four to a minimum of 12 lanes between Islington Avenue and Markham Road.

[136] Between June 1990 and 1998, Highway 401 and Interstate 75 were used for a pilot project named Advantage I-75 to test the reliability and versatility of an automated tracking system for transport trucks.

[140][142] Various other names, including The Killer Highway circulated for a time,[143] but Carnage Alley became predominant following an 87-vehicle pile-up on September 3, 1999 (the start of Labour Day weekend), the worst in Canadian history, that resulted in eight deaths and 45 injured individuals.

[145] On the morning of September 3, the local weather station reported clear conditions due to a malfunction,[144] while a thick layer of fog rolled onto the highway.

[146][147] Immediately following the crash, the MTO installed paved shoulders with rumble strips[148] and funded additional police to patrol the highway, a move criticized as being insufficient.

As part of that project, the Dougall Parkway split with Highway 401 was reconfigured, replacing a one-lane 1950s-era underpass tunnel with a modern high-speed flyover ramp.

[153] This length of the highway is often travelled by a convoy of vehicles carrying a fallen soldier's body, with his or her family, from the military airport at CFB Trenton to the coroner's office at the Centre of Forensic Sciences in Toronto.

[154] The origin of the name can be traced to an article in the Toronto Sun on June 23, 2007, by columnist Joe Warmington, in which he interviewed Northumberland photographer Pete Fisher.

[161] The project included the installation of a tall-wall median barrier, straightening curves and adding additional interchanges on the freeway, allowing it to be easily vacated in an emergency event.

[179][180] On March 3, 2008, the Michigan Department of Transportation and the MTO (in partnership with Transport Canada, the Federal Highway Administration of the United States and the Detroit River International Crossing group) completed a joint assessment on the soils along the Detroit River and determined they could indeed support the weight of a new bridge; the stability of the underlying soil and clay and the impact of the nearby Windsor Salt Mine had caused concern for all parties involved in the project.

[181] Despite protest from area residents,[182] as well as a dismissed lawsuit from Ambassador Bridge owner Matty Moroun,[176][177] it was announced on May 1, 2008, that a preferred route had been selected for the Highway 401 extension which would be named the Windsor–Essex Parkway.

[190] The original North Talbot Road overpass was demolished on August 20, 2011, to make way for the widening of the existing freeway from four through-lanes, however the replacement bridge was closed in December 2013 due to faulty concrete girders and rebuilt by May 2014.

[16] In Southwestern Ontario, several improvements are under way to provide six lanes on Highway 401 from Windsor to Toronto,[203] in response to the higher-than-average accidents occurring on the "Carnage Alley" stretch including the 1999 Labour Day weekend pileup.

Just west of the Highway 8 interchange, the freeway's existing six-span Grand River Bridges (opened in 1960, restriped in the early 1990s from two to three lanes per direction) are being replaced with two new four-span structures, a project scheduled for completion in 2025.

[227] On September 25, 2024, Premier Doug Ford announced that the Ontario government has launched the technical evaluation for the proposed construction of a new driver and transit tunnel expressway under Highway 401.

In Mississauga (just east of Winston Churchill Boulevard), a centre with a unique layout opened in 1991 but closed in 2006, being demolished in 2010 to accommodate the freeway's widening to a collector-express system as well as making way for an OPP station.

An aerial image of an 18-lane freeway. The freeway is divided into four separate set of lanes, known as carriageways.
Looking east at the widest segment of Highway 401 which is near Toronto Pearson International Airport . In the foreground is the interchange with Dixie Road.
Highway 401 looking west at split with Highway 402 in London .
Highway 401 eastbound express lanes at Weston Road. This section has a volume of over 500,000 vehicles per day during the summer months.
Different colours are used on the signs on Highway 401's collector-express system to avoid confusion. The express lanes use green signs and the collector lanes use blue.
"The Basketweave", just east of the Highway 400 interchange, is a free-flowing crossover between the collector and express lanes.
Oriole GO Station looking north at Highway 401.
Highway 401 looking west from Don Mills Road overpass, with the Concord Park Place condo development and North York General Hospital in the background.
Highway 401 just west of Leslie Street
A four-lane divided highway among short hills travels into the background and curves to the right. The two divided halves are separated by a depressed swampy median.
Through much of eastern Ontario, Highway 401 is a rural freeway with a grass median .
"A look down a rather level two-lane asphalt highway, with cars and trucks at some distance traveling in the same direction. Oncoming vehicles use the two-lane roadway some 3 or 4 metres to the left, separated by a grassy median. Orange signs and barrels to the right indicate construction work and farther to the right, a tall blue-and-white sign and flags welcome motorists to Quebec."
Highway 401 ends at the Quebec border, where Autoroute 20 continues towards Montreal and the Maritime provinces .
A map with legend of
Highway 401 colour-coded by the year each section opened to traffic
A black and white photo shows a smooth, gravel, divided roadway with a grass median. There are no safety features such as guardrails.
Finished grading of the Thousand Islands Parkway (Highway 2S) in 1944
A four-leaf clover shaped highway junction, located in the midst of developing suburbs.
The Highway 400 interchange in 1953. Today, the former cloverleaf has been replaced with a multilevel interchange .
A black-and-white photo shows a four-lane freeway divided by a grass median. In the oncoming lanes, traffic is congested into the distance. With few exceptions, the 401 is surrounded by farmland.
Within years after opening, the four-lane Toronto Bypass was congested, prompting the Department of Highways to widen this section to 12 lanes beginning in 1963.
A blue plaque on a stone wall. The plaque has a yellow border, and is mostly rectangular in shape, with the long end oriented horizontally. However, the top side has a camel hump in the centre, with a circle centred at the top of the hump. Inside the circle is an Ontario coat-of-arms. The plaque reads: THE MACDONALD CARTIER FREEWAY This plaque commemorates the completion of the Macdonald-Cartier Freeway (Highway 401), the longest freeway operated without tolls by a single highway authority in North America. Covering 510 miles between Windsor on the Canada–US border and the Ontario-Quebec boundary, it serves the richest economic region in Canada. In January 1965, it was named by The Honourable John Robarts, Premier of Ontario, in honour of the two founding architects of the Confederation of Canada, Sir John A. Macdonald and Sir George-Étienne Cartier. This site is located on the last section of construction, consisting of 15 miles between Ivy Lea and Highway 2, which was completed on October 11, 1968.
A plaque near Brockville commemorates the official completion of the highway.
A bird's-eye view of a large highway interchange under construction. Several bridges are complete, but nothing is paved, aside from one highway crossing horizontally, which detours between the bridges.
The widening of Highway 401 from four to twelve lanes in Toronto took nine years and was accomplished with at least four lanes open at all times. Shown here is the Highway 401 / Don Valley Parkway interchange (which replaced an earlier interchange with Woodbine Avenue , and would link to the future Highway 404 ) under construction in 1965.
Driving down a six-lane highway during the day. In front is a concrete bridge. The highway curves to the right as it passes beneath the bridge.
Highway 401 at Meadowvale Road in 1989, before being widened to a 14-lane collector-express system
Hwy. 401 widening work in Mississauga looking east from the Mississauga Road overpass in 2020
"A highway viewed from high above travels into the distance from the bottom-right to the top-left. An overpass allows a road to cross the highway near the bottom of the image. The surroundings are entirely agricultural. On the highway, several vehicles are piled into each other. The middle of the large pileup is smoking."
The 87-vehicle pile up on September 3, 1999
Highway 401 facing southwest in 1958, at the interchange with then- Highway 98 (now Provincial Road) in the foreground, and the split at Dougall Parkway in the background. This segment would be reconstructed in 2008–10.
A bridge showcased against the sky, with the ground not visible. Lining the bridge are people, some holding Canadian flags.
Canadians line overpasses along the Highway of Heroes to pay their respects to fallen soldiers.
A Highway of Heroes reassurance marker with a red poppy flower in place of a number. Above that is the text Highway of Heroes, and below it SUPPORT OUR TROOPS.
The reassurance marker for the Highway of Heroes
Highway 401 was widened in 2008 between Highway 402 and Wellington Road in London . Additional widening west of Highway 402 is planned.
An empty freeway in the middle of a city.
An empty Highway 401 through Toronto following a series of propane explosions in 2008 .
The Highway 401 extension in Windsor , opened in 2015, showing the below-grade portion with tunnels and greenspace. It will connect to the Gordie Howe International Bridge .
Highway 401 in the Greenbelt , at the interchange with Guelph Line. The stretch of Highway 401 between Highway 8 and Highway 407 ETR is slated to be widened from six to ten lanes, including two HOV lanes.
Highway 401 eastbound at the French Line Road interchange
ONroute Cambridge South service station