The 400-series highways are a network of
controlled-access highway
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms ...
s in the
Canadian
Canadians () are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of their being ''C ...
province of
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
, forming a special subset of the
provincial highway system. They are analogous to the
Interstate Highway System
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...
in the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
or the
Autoroute system of neighbouring
Quebec
Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...
, and are regulated by the
Ministry of Transportation of Ontario
The Ministry of Transportation (MTO) is the provincial ministry of the Government of Ontario that is responsible for transport infrastructure and related law in Ontario, Canada. The ministry traces its roots back over a century to the 1890s, w ...
(MTO). The 400-series designations were introduced in 1952, although Ontario had been constructing divided highways for two decades prior. Initially, only Highways
400
__NOTOC__
Year 400 (Roman numerals, CD) was a leap year starting on Sunday of the Julian calendar. In the Roman Empire, it was known as the Year of the Consulship of Stilicho and Aurelianus (consul 400), Aurelianus (or, less frequently, year ...
,
401 and
402 were numbered; other designations followed in the subsequent decades. To this day, not all
controlled-access highways in Ontario are a part of the 400-series highway network. The network is situated almost entirely in
Southern Ontario, although
Highway 400 extends into the more remote
northern portion of the province.
Modern 400-series highways have high design standards,
speed limit
Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, express ...
s of , with a limit on select stretches, and various collision avoidance and traffic management systems. The design of 400-series highways has set the precedent for a number of innovations used throughout
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
, including the
parclo interchange and a modified
Jersey barrier design known as the Ontario Tall Wall. As a result, they currently experience one of the lowest accident and fatality rates comparative to traffic volume in North America.
History
When the 400-series designations were first applied to Ontario freeways in 1952,
several divided highways had already been opened in Southern Ontario.
Originally inspired by German
Autobahns, Minister of Highways
Thomas McQuesten planned a network of "Dual Highways" across the southern half of the province during the 1930s.
The
Queen Elizabeth Way (QEW) was first, an upgrade to the partially constructed
Middle Road in 1934.
McQuesten also sought out the economic opportunities that came with linking Toronto to
Detroit
Detroit ( , ) is the List of municipalities in Michigan, most populous city in the U.S. state of Michigan. It is situated on the bank of the Detroit River across from Windsor, Ontario. It had a population of 639,111 at the 2020 United State ...
and
New York state
New York, also called New York State, is a state in the northeastern United States. Bordered by New England to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and ...
by divided roadways with interchanges at major crossroads. Although he no longer served as Minister of Highways by the onset of
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
, his ambitious plans would come to fruition in the following decades as Highways 400, 401, 402, 403 (between Woodstock and Hamilton), and 405.
The construction boom following the war resulted in many new freeway construction projects in the province. The Toronto–Barrie Highway (Highway 400), Trans-Provincial Highway (Highway 401),
a short expansion of Highway 7 approaching the
Blue Water Bridge in Sarnia (Highway 402),
and an expansion of Highway 27 (eventually designated as Highway 427 by the mid-1970s) into part of the Toronto Bypass were all underway or completed by the early 1950s.
Seeking a way to distinguish the controlled-access freeways from the existing two-lane King's Highways, the Department of Highways created the 400-series designations in 1952. By the end of the year, Highway 400, 401, and 402 were numbered, although they were only short stubs of their current lengths.
Highway 401 was assembled across the province in a patchwork fashion,
becoming fully navigable between Windsor and the Quebec border on November 10, 1964;
[.]
Highway 400 was extended north to
Coldwater on Christmas Eve 1959;
Highway 402 was extended to London between 1972 and 1982.
In addition to this network backbone, plans for additional 400-series highways were initiated by the late 1950s, comprising the Chedoke Expressway (Highway 403) through
Hamilton;
the
Don Valley Parkway Extension (Highway 404) northward from the soon-to-be constructed Toronto expressway;
Highway 405 to connect with the American border near
St. Catharines;
Highway 406 south from St. Catharines to
Welland;
Highway 407 encircling the Greater Toronto Area (GTA), though not built for another 40 years;
Highway 409 to connect Highway 401 with
Toronto International Airport;
and The Queensway (Highway 417) through Ottawa.
The first sections of these freeways were opened in 1963,
1977,
1963, 1965,
1997,
1974,
and 1960,
respectively.
Throughout the 1960s and 1970s, additional freeways were planned or built, including Highway 427 in Toronto,
Highway 403 through Mississauga,
Highway 410 north to Brampton and Highway 416 to connect Highways 401 and 417.
Highway 420 was designated in Niagara Falls,
though it had been built as part of the QEW in 1941. Other major works included the skyway bridges along the QEW and the expansion of Highway 401 through most of Toronto into twelve-lane
collector–express systems.
By the mid-1980s, the network had more-or-less taken its current shape, with only Highways 407, 412, 416 and 418 yet to be built.
Instead, emphasis was placed on expanding existing routes to accommodate increasing traffic volumes.
However, extensions of Highway 400 towards
Parry Sound,
Highway 403 between
Woodstock and Hamilton,
Highway 404 towards
Newmarket,
and Highway 427 towards Vaughan were underway.
By the end of the decade, construction of Highway 407 and Highway 416 had begun,
and Highway 410 was expanded from two to four lanes.
Highways 407 and 416 opened in the late 1990s.
Until early 2015, Highways 407 and 416 were the most-recently designated (and constructed) freeways in Ontario. This has changed with the construction of
Highways 412 and
418. In addition to these new additions to the 400-series network, several extensions of existing freeways have been built or are underway,
including Highway 410 north of Brampton in 2009,
Highway 400 to north of Parry Sound in 2010,
Highway 417 to
Arnprior in 2012,
Highway 404 to
Keswick in 2014,
Highway 401 through Windsor in 2015,
and four-laning Highway 406 to Welland in late 2015.
Design standards
The 400-series highways always have a minimum 4 lane cross-section with grade separation at all junctions. Interchanges tend to be spaced at least 1.5 kilometres apart in urban areas unless there are basket weave ramps or collector lanes to facilitate shorter merge distances. In rural areas, interchanges tend to be spaced at least 3 kilometres apart, although exceptions exist. When the cross-section of highway is larger than 10 lanes, the road is usually arranged into a
local–express lane system, which exist on sections of Highways 400, 401, 403, 404 and 427. On all but a few interchanges in the whole system, ramps merge freely on the highway except if there are
ramp meters in use, and stop or yield controlled ramps are rare. An interchange with stop-controlled ramps onto Highway 400 at Canal Road is currently scheduled for replacement.
While older freeways have some lapses in safety features, contemporary 400-series highways have
design speeds of ,
speed limit
Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, express ...
s ranging from to , various collision avoidance and traffic management systems, and several design standards adopted throughout North America.
Of note are the
Ontario Tall Wall median barrier and the
Parclo A-4 interchange design, the latter which became standard in the design for the widening of Highway 401 through Toronto in 1962. The
Institute of Traffic Engineers subsequently recommended this design to replace the cloverleaf interchange throughout North America.
Ontario highways rank fourth in North America for fatality rates, with 0.61 fatalities per 10,000 licensed drivers in 2017. However, this also includes two-lane provincial highways.
On May 1, 2019, the government of Ontario was looking towards raising the speed limits of the 400-series highways up to
Jeff Yurek, Transportation Minister at that time had stated that "The 400-series highways were built for, I believe, a speed limit of 120 km/h safely."
A trial was set up on three stretches of highways on September 26, 2019, to test the viability of increasing speed limits.
The three trialed sections along with three more sections were permanently changed to the higher speed limit on April 22, 2022, and two more sections were trialed. The two trialed sections were made permanent along with 10 more sections on July 12, 2024. On October 2, 2024, Premier
Doug Ford mentioned in a press conference that he had directed Transportation Minister
Prabmeet Sarkaria to raise the speed limit on all remaining 400-series highway sections “where it is safe to do so”.
Conforming with the ''
Manual on Uniform Traffic Control Devices'', Ontario utilizes green signs for guidance purposes, including distances to nearby interchanges and destinations.
Generally, blue signage is used to list services and attractions at upcoming exits, known as
Tourism-Oriented Directional Signing.
However, several exceptions exist, notably blue guidance signage for toll highways such as
Highway 407, in addition to the
collector lanes of highways.
The baseline standard for the construction of or expansion to a freeway in Ontario is an
average daily traffic count of 10,000 vehicles per day. However, other factors are considered as well, particularly future traffic volume forecasts. To promote economic development in a disadvantaged region (e.g., the current extension of Highway 400 to
Northern Ontario
Northern Ontario is a primary geographic and quasi-administrative region of the Provinces and territories of Canada, Canadian province of Ontario, the other primary region being Southern Ontario. Most of the core geographic region is located on p ...
), a 400-series highway may be built where the existing highway's traffic counts fall below 10,000.
The MTO plans and finances the construction and maintenance of the King's Highway system, which includes the 400-series network.
The system includes of freeways. Highway 401 is the longest freeway at , in addition to being the widest and busiest road in Canada. Highway 420 is the shortest of the routes at .
There are four examples of 400 series standard highways in Ontario that are not signed as such. The
Gardiner Expressway between Highway 427 and Parklawn Road was originally built as a section of QEW (Hwy 451) and therefore is built to 400-series standards but lost its QEW designation after being downloaded to the City of Toronto. The section of
Highway 7 between the town of
Carleton Place and its junction with Highway 417 is also built to 400-series standards, but a 400-series designation has yet to be applied.
Highway 69 between Sudbury and Key River is built to 400-series standards in anticipation of it becoming part of Highway 400 once the gap between the two freeways is filled.
Highway 115 north of Highway 35/Highway115 concurrency and Peterborough is also built to 400-series standards, however a 400-series designation has yet to be applied. Most other freeways and expressways in Ontario that lack a 400-series designation have lower construction standards, lower design speeds and lower speed limits.
High-occupancy vehicle lanes

The MTO began planning for the use of
high-occupancy vehicle (HOV) lanes with the HOV Opportunities Study, contracted to
McCormick Rankin in 2001. This led to the test trial of three HOV lanes in the GTA in December 2005: southbound Highway 404 between Highway 7 and Highway 401, with a dedicated HOV ramp built to connect with westbound Highway 401, and Highway 403 in both directions between Highway 407 and Highway 401 in Mississauga.
Since then, HOV lanes have been opened on several 400-series freeways around the
Golden Horseshoe and
National Capital Region. In May 2007, the MTO introduced a multibillion-dollar Horseshoe Network Project, which included plans to incorporate HOV lanes into numerous 400-series highways.
By then, work was already advanced on several projects, including the northbound HOV lane on Highway 404 (that opened on July 23, 2007) and an HOV lane along both directions of Highway 403 between Highway 407 and Highway 401. A third pair of HOV lanes has since been introduced to the QEW/403 through Oakville, and a fourth individual HOV lane travels eastbound on Highway 417 from just west of
Eagleson Road in
Ottawa
Ottawa is the capital city of Canada. It is located in the southern Ontario, southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Gatineau, Quebec, and forms the cor ...
to just east of Moodie Drive.
More than of HOV lanes are currently proposed for construction by 2031. Future plans include extending existing HOV lanes and introducing them to other 400-series freeways.
, two projects have been confirmed: Highway 410 between Highway 401 and Queen Street in Brampton, and Highway 427 between Highway 409 and Highway 7. The MTO has stated that HOV lanes will only be introduced through new construction and that no general-purpose lanes will be converted. The general goals of the project are to help increase highway efficiency (an HOV lane is claimed by the Ontario government to have the ability to move as many people as four general-purpose lanes),
reduce congestion, conserve energy and help protect the environment.
During the
2015 Pan American Games and
2015 Parapan American Games held in
Toronto
Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...
, several HOV lanes had their minimum requirements increased from two passengers to three, and some highways had their general-purpose lanes temporarily converted to HOV lanes to accommodate increased traffic. These temporary restrictions lasted from June 29 to August 18.
2021 saw several new HOV lanes opened. The southbound HOV lane on Highway400 between King Road and Major Mackenzie Drive was opened on September11, 2021; while the northbound lane opened two months later on November11. The Highway427 extension, which opened on September18, included an HOV lane north of Finch Avenue.
Future HOV lanes
The following table lists planned expansions to the HOV network by 2040.
Planned extensions and new routes
Existing network
Gallery
File:Highway 401.png, Highway 401 south of Pearson Airport is the widest freeway in Canada, and one of the widest and busiest in the world
File:Highway 410 Start.jpg, Aerial view of the interchange between Highway 401, 403 and 410 in Mississauga
File:416 into Ottawa.png, An aerial view of Highway 416 approaching Ottawa
File:409-427 Interchange.jpg, A sprawling interchange between Highway 409 and 427 in Etobicoke, one of several in the Greater Toronto Area
File:Derry and 407.jpg, The Parclo interchange design is used throughout the 400-series network
See also
*
List of provincial highways in Ontario
*
100-Series Highways of Nova Scotia
*
400-series Highways of British Columbia
*
Quebec Autoroutes
References
Sources
Bibliography
*
*
*
*
*
External links
Ontario Ministry of Transportation
Highway Construction Programs
Photographs and history on the 400-Series Highways (and other provincial highways, too)*
Dirt Roads to Freeways ... And All That'', ca. 1978, Archives of Ontario YouTube Channel
{{Ontario Controlled Access Highways
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...