The King's Highway 401 (also known as the Macdonald-Cartier Freeway) is a highway that extends across Southern Ontario, Canada. It is the longest 400-Series Highway in Ontario, and one of the widest and busiest highways in the world. In fact, the segment of Highway 401 passing through Toronto has the distinction of being North America's busiest freeway. Together with Quebec Autoroute 20, it is the road transportation backbone of the Quebec City-Windsor Corridor, along which over half of Canada's population resides. Colloquially, the road is known simply as the 401, spoken as "four-oh-one."

In 1965, Lieutenant Governor of Ontario William Earl Rowe issued an Order-in-Council, on the advice of then-Premier John Robarts, designating Highway 401 the Macdonald-Cartier Freeway, to honour both Sir John A. Macdonald and Sir George-Étienne Cartier, two of the Province of Canada's Fathers of Confederation, and in recognition of Canada's upcoming centennial celebrations in 1967. This name is found on maps and official documents, but seldom used in conversation or on modern road signs.

On August 24, 2007, the stretch of highway between Toronto (from Highway 404/Don Valley Parkway) and Trenton (from Glen Miller Road) was given the additional name Highway of Heroes, in honour of Canadian Forces personnel killed during the War in Afghanistan.

Overview

Highway 401 begins at Highway 3, 13 km from the Detroit River on the outskirts of Windsor (not at the Michigan border as some mistakenly assume, though the exits on the freeway are listed as distances from the Ambassador Bridge) and ends at the Quebec border, 818 km away. There are 18 rest areas or service centres located along the route, allowing motorists to access services without leaving the highway. A plaque was erected at the Mallorytown oasis, located on the last section of the freeway to be completed, stating that the 401 was the longest non-toll freeway under a single highway authority in North America. (Today the section of Interstate 10 in Texas holds this record.)

Major freeway junctions are located at these roads and highways: 402, Highbury Avenue (London), 403, 8, 6, 407, 410, 427, 400, Allen Road (Toronto), 404 and Don Valley Parkway (Toronto), 35 and 115, 416. Quebec Autoroute 20 continues the highway at its eastern end.

Highway 401 currently has no direct connections with U.S. Interstate highways, but Interstates 75, 94, 96 and 375 in Detroit, Michigan, and Interstate 81 in New York State are each a short distance away, via Highways 3, the former 3B, and 137, leading to the Ambassador Bridge, the Detroit-Windsor Tunnel, and the Thousand Islands Bridge, respectively. Highway 402 also links Highway 401 to I-69/I-94 via the Bluewater Bridge in Sarnia, Ontario. An extension to a potential border crossing with Michigan in the western portion of Windsor may eventually connect to a spur Interstate in Detroit, Michigan, but no routing on the extension has been determined yet.

Transportation corridor

The 401 is one of the world's busiest highways, with an estimated Annual Average Daily Traffic (AADT) of over 500,000 in 2006, between the Weston Road and Highway 400 interchanges in Toronto. Due to its triple use as the main trade, commuting and recreational corridor in Ontario, 24-hour traffic volumes can exceed the 500,000 level on some days. The just-in-time inventory systems of the highly integrated auto industry in Michigan and Ontario have made the highway the busiest truck route in the world. Highway 401 also includes the world's busiest multi-structure bridge at Hogg's Hollow in Toronto (four structures for the highway's four roadway beds). The first of these structures served as a bypass for Highway 11, and was built in 1929, with the three others being built more recently (1960s).

The 401 is a strategically important highway in Canada, as it connects the populous Southern Ontario region with Quebec and Michigan, while also connecting to most other major highways in the province. The 401 also acts as a 'short cut' between Detroit and Buffalo, New York (via Queen Elizabeth Way and Highway 403), and is used by many American motorists for this reason. The highway also serves as the principal connection to Montreal and points east, including New England, becoming Autoroute 20 at the Quebec border. The border crossing at Windsor and Detroit is the busiest trade crossing in the world, and although the 401 itself does not physically extend the last few kilometres into Detroit, it is the only route from Toronto to Windsor and on to Interstate 75 (aside from the Blue Water Bridge in Sarnia via Highway 402 and I-69/I-94). A future expansion of the Windsor-Detroit border crossing, which will include a freeway bypass of the existing Highway 3, may result in Highway 401 having a direct freeway link to the border. The route and type of roadway built is causing much debate in the Windsor area, with the city opting for a partially covered roadway with parks on top. However, the provincial and federal governments of Canada are seemingly opting for a cheaper less-effective solution, likely to be a simple at-grade highway extending to the new crossing. Some 40% of Canada-U.S. trade travels the highway, representing one-third of Canada's foreign trade, and 4% of all U.S. foreign trade. However, it is not part of the Trans-Canada Highway.

Collector-express sections

Today the stretch of Highway 401 that passes through the Greater Toronto Area ranges from 6 to 18 lanes, which makes it the world's widest highway.

Islington Avenue to Brock Road

The section that now runs through Toronto was a rural roadway that was entirely outside of the Toronto city limits when first opened, and was originally referred to as the Toronto Bypass. The new freeway attracted development all along its length. As the city's suburbs grew, it quickly became an urban commuter road, rather than a long-distance bypass route as was originally planned, leading to extensive traffic jams.

This was a problem/opportunity solved and built upon to some extent by implementing separate express and collector lanes, similar to the express/local set-up of the Dan Ryan Expressway in Chicago. Transfers, such as The Basketweave allow traffic to move from the express to collector lanes and vice versa.

Though Highway 401's collectors are intended more for urban commuters, they enjoy equal access to intersecting freeways as the express lanes do, such as at the junctions with Highway 404 and somewhat with Highway 400, so their use is not restricted to local traffic. The configuration also facilitates road maintenance, as the MTO can close off either the express or collector lanes for night repairs or upgrades. By contrast, the collector-express system on Highway 427 separates out two streams of traffic; the express lanes connect the QEW/Gardiner with 401 and exclusively lead to freeway-to-freeway ramps, while the collector lanes link up the arterials Highway 27 and Brown's Line and have interchanges with local traffic.

By 1967 Highway 401 was widened from four lanes to 12 or more through Toronto from Islington Avenue to Warden Avenue. In the early 1970s the collector express lanes were extended to Neilson Road and eastward to Brock Road by 1997.

The main collector-express setup with a minimum 12-lane cross-section currently stretches from Islington Avenue to Brock Road. Highway 409, which branches off from Highway 401 just west of Islington to Toronto Pearson International Airport, has been unsuccessful in diverting traffic volumes; the 10-lane segment between Islington and Highway 427 is highly congested as a result. The existing 401-427 interchange is considered one of the worst bottlenecks since it only allows eight lanes of traffic (four in each direction) to pass through the interchange. It initially only allowed six lanes of through traffic until a widening project was completed in 2005; a major reconstruction of the junction is needed to meet current demands, estimated at five to six lanes.

An alternative plan to the collector-express setup was to construct a bypass of Highway 401. This project was revived in 1987 and opened in 1997 as the toll road Highway 407 ETR to parallel Highway 401 in the Greater Toronto Area.

Signage

In order to make sure drivers are not confused by signs appearing in other lanes, colours have been assigned to both Collector and Express Lanes. Collector lanes (handling traffic merging from and to exits) are blue while Express Lane signs are green. Due to the urban nature of the road, all signs are mounted overhead on gantries. The green signs list up to three upcoming exits (for example: Leslie St, Bayview Ave, Yonge St, 4 km). However, the mileages indicated on the signs do not indicate the actual distance to the next exit, they only indicate the distance to the next transfer to the collectors. Once in the collector lanes, the blue signs direct and inform drivers of the distance until the exit ramp (for example: Leslie Street, 1 km).

Highway 403/410 to Highway 427

Highway 401 has a separate collector-express system in Mississauga between the junctions with Highways 403/410 and Highway 427. This was completed in 1986, concurrent with the expansion of the 401-403 interchange and the addition of two express flyover ramps and includes an eastbound collector-express transfer known as the "Tunnel." At 18 lanes wide this is the widest section of Highway 401, although at the present only nine lanes are designated for 401 through traffic (as express lanes) while the collector lanes serve as direct connections or ramp extensions from 403/410 to 427.

The existing 401/427 interchange remains a bottleneck to possible eastward expansion of this configuration that would link it up with the Islington-Brock collector-express system. Another choke point is at the 403/410 interchange since the 401 narrows down to eight lanes west of that junction. However, that junction has been designed with westward expansion of the collector-express system in mind; several prerequisite projects to accommodate widening from 403/410 to Mississauga Road were underway in the late 1990s, including a new interchange at Mavis Road and the reconstruction of the Mississauga Road and Derry Road overpasses.

History

The need for a four-lane bypass of Highway 2 in the Oshawa area was growing in the early 1930s, as the simple two-lane road could no longer handle the growing levels of traffic. The idea for a roadway similar to Middle Road in Peel County was led by Thomas McQuesten, then head of the Department of Highways.

Construction began on two portions of Highway 401 before the beginning of the Second World War: the new Kingston Road from Highland Creek to Oshawa (the modern day former Highway 2A), which bypassed the Kingston Road (Highway 2), and the scenic highway (now the Thousand Islands Parkway) from Gananoque to Brockville, also bypassing a portion of Highway 2. The former was built because of heavy traffic between Toronto and Oshawa, and the latter to connect with the Thousand Islands Bridge, opened in 1938. In late 1941 or early 1942, the scenic highway was opened to local traffic as a gravel road, and numbered Highway 2S, for "Highway 2 Scenic" (as opposed to the popular, but incorrect, idea of "Highway 2 South", since the road does lie fully south of Highway 2). Paving of the south side, the future eastbound lanes, was completed several years later.

Construction of the first segment, from Highland Creek to Oshawa, was initiated in 1938. Much of the grading and a number of structures were completed before the Second World War, at which time most of the construction work was suspended. This section was finally completed and opened to traffic in 1947.

During the Second World War, the provincial government undertook a number of surveys and studies to determine the most desirable route for the new limited-access highway.

The highway was redesignated "Highway 401" in 1952. The last segment, between Gananoque and Brockville, was completed in 1968 to bypass what is now the Thousand Islands Parkway (which included at-grade intersections and private entrances). The last at-grade intersection on the present alignment was at Joyceville Road, east of Kingston, which was converted to an interchange with the final 1968 construction.

Much of the current routing of Highway 401 across Toronto was built in 1954 (when the entire area was north of the city) as the "Toronto By-Pass". The road ended temporarily at the Weston Road interchange (now Exit 357), while a bridge across the Humber River was constructed for the road to be extended westwards. This bridge was never used, as just a few months later, Hurricane Hazel damaged it so badly that it had to be dynamited and completely rebuilt. This delayed Highway 401's completion in the Toronto area for nearly a year.

Through much of the 1950s, motorists were annoyed with the perceived snail's pace of constructing the freeway, and had pressured the provincial government to speed up the completion of Highway 401, with much of the public supporting turning Highway 401 into a tolled road to accelerate construction. To do this, the provincial government had assigned the "Select Committee on Toll Roads and Highway Financing" in 1955 to consider any benefits or disadvantages from this. The resulting report from the committee was in by 1956, and the result was that tolling the roadway would be extremely detrimental. Tolls would appear on the 400-series network, if only temporarily. When the St. Lawrence Seaway was built in the late 1950s, drivers on the Queen Elizabeth Way paid tolls on the newly-built Garden City and Burlington Bay skyways until 1973, as a way to recover the costs of construction and upgrades.

During the late 1950s, the road was extended from Windsor to London as an at-grade Super 2, before being twinned in the 1960s (the segment from Windsor to Tilbury was completed as a four-lane freeway), with the eastbound carriageway being built first. This is still evident today, as many bridges over creeks and streams in the area have different ages and appearances. The section from Windsor to Tilbury was among the original sections built, from 1952-1958, with the Tilbury Bypass (from Exit 56 to Exit 63) being constructed in 1961, with the Tilbury-London section opening in 1963. In 1957, the London-Woodstock section opened, as a four-lane divided freeway from Highway 4's interchange (just west of London), to Highway 2's interchange (just east of Woodstock). The road would later be extended to Kitchener in 1961, where it was linked to the Kitchener-Toronto-Oshawa section.

In 1964, Highway 401 was diverted from its former alignment in Windsor, Ontario along what is now Dougall Parkway, to its current terminus with Highway 3, with the overpass carrying Highway 3's westbound lanes being built in 1956 in anticipation of the extension. The former alignment became Highway 401A (a secret designation, much like Highway 400A in Barrie). At this time, Highway 401 was also twinned from Windsor (interchange with Highway 98, now Provincial Road) to the eastern interchange (Exit 63) with Highway 2 in Tilbury, with two new lanes being constructed north of the existing lanes. The new carriageway became the westbound lanes, while the original two-lane carriageway became the east-bound lanes. This twinning from Windsor to Tilbury was completed in 1965. By 1968, all of Highway 401 was twinned to a minimum of four lanes.

In 1965, Lieutenant Governor of Ontario William Earl Rowe issued an Order-in-Council, on the advice of then-Premier John Robarts, designating Highway 401 the Macdonald-Cartier Freeway, to honour both Sir John A. Macdonald and Sir George-Étienne Cartier, two of the Province of Canada's Fathers of Confederation, and in recognition of Canada's upcoming centennial celebrations in 1967. This name is found on maps and official documents, but seldom used in conversation or on modern road signs. Macdonald's name is misspelled on Internet mapping services, such as Google Maps and Microsoft Virtual Earth, in spite of repeated requests to data supplier Navteq to correct the error. A 1961 proposal to name the highway the Leslie M. Frost Thruway, after the recently retired Premier of Ontario, was approved by the provincial cabinet, but was never carried on to receive Royal Assent.

"Carnage Alley"

The section of Highway 401 between Windsor and London has become known as "Carnage Alley", particularly since 1988, when a long string of particularly violent and deadly accidents occurred in this section.

These accidents have occurred because of the road's initial 1950s design, particularly narrow lanes, soft shoulders, and a narrow grass median which have been insufficient in preventing cross-directional collisions. This stretch of highway is also the busiest truck route in North America.

One of the more accident-prone parts of the freeway is at Exit 109 (Victoria Road, formerly Highway 21, now Chatham-Kent Roads 17/21). The freeway curves immediately east of the interchange and many people are not used to a curve near an interchange, particularly on the Windsor-London stretch of freeway, which is mainly straight.

Ironically, the Windsor-London segment's largely-straight and flat alignment has also led to accidents due to its monotonous and unengaging nature, resulting in drivers being prone to falling asleep at the wheel. The flat terrain surrounding the freeway offers no shelter from the wind, so winter storms blow snow across the highway, where the traffic polishes it to a nice sheen for ice to build up. These crosswinds-along with ice, driver fatigue, gravel shoulders and aggressive driving-combined to create an automotive "Bermuda Triangle".

This segment of Highway 401 was the site of Canada's deadliest automobile pile-up on September 3 1999 (Labour Day weekend). An 87-vehicle crash occurred on the freeway just east of the Manning Road interchange and truck inspection centre, during a thick fog, killing seven and injuring 40 others. The motorists were not provided with warning of the fog, as the weather station in that region had malfunctioned that day.

The MTO immediately added paved shoulders and rumble strips, and provided funding for additional police to be hired to patrol this stretch. The Canadian Automobile Association (CAA) described these steps as a "quick-fix", as their preferred solution is to replace the grass median with a concrete barrier and an additional lane per direction; this is a long-term plan of the Ministry. For more on this, read below.

Speeding and tailgating

Many of the accidents described earlier are attributed to speeding and tailgating (following too closely), causing many motorists in Ontario to consider having the MTO raise the speed limit on 400-series highways from 100 km/h to 110-120 km/h, bringing the network in line with comparable freeway networks in the United States, Europe, and other provinces such as Alberta. The speed limit was reduced from the pre-metric 70 mph in 1974 by act of Provincial Parliament. The basis for this reduction was improved safety, unlike the reductions in US speed limits at the same time.

Recently, to combat excessive speeding, the Ontario Provincial Legislature, on the recommendation of the Ministry of Transportation and the Ontario Provincial Police, has passed a law that allows police to immediately suspend the driver’s licence and impound the vehicle involved for seven days in the case of "excessive speeding" (driving 50 km/h over the limit, or over 150 km/h on 400-series highways). Transport trucks are also going to be limited by speed governors to 105 km/h, the same as in nearby Ohio, with mixed public sentiment on the matter.

In contrast with proposals for raising the speed limit, there has been growing grassroots support for a revival of photo-radar with a twist: the total proceeds from photo-radar fines are diverted to a specific charity such as a local hospital emergency room (where many highway traffic accident victims end up) overcoming previous objections to photo-radar where fines were perceived by the public to be mixed with the government's general tax revenue. However, opponents of photo-radar argue that it does not address the root causes of speeding.

Highway of Heroes

On 24 August 2007, the Ministry of Transportation (MTO) announced that the stretch of Highway 401 between Glen Miller Road, in Trenton, and the intersection of the Don Valley Parkway and Highway 404, in Toronto, would bear the additional name Highway of Heroes, in honour of Canada's fallen soldiers (notably those who died on duty in Afghanistan), though Highway 401 in its entirety remains designated as the Macdonald-Cartier Freeway. This length of the freeway is often travelled by a convoy of vehicles carrying a fallen soldier's body, with his or her family, from CFB Trenton to the coroner's office at the Centre for Forensic Sciences in Toronto, and since 2002, when the first of Canada's fallen soldiers were returned from Afghanistan, crowds from communities along this part of the 401 lined the overpasses to pay their respects as convoys passed. Large signs and several smaller reassurance markers with the new designation have been added along the Highway of Heroes; similar to the older and discontinued M-C Freeway shields installed in the 1960s, the King's Highway shields, along with two shields with a poppy symbol (one with 401 designation and two with poppies with text Highway of Heroes and Autoroute des héros), appear after each on ramp along the route. The name's origins can be traced to June 25, 2007 when Toronto Sun columnist Joe Warmington first described people standing on Highway 401 bridges from Trenton to Toronto as a “Highway of Heroes” phenomenon.

The billboard version of the Highway 401 Highway of Heroes sign.	The King's Highway shield version of the Highway 401 Highway of Heroes sign.

Future expansion and upgrades

In the 1950s, Highway 401 had initially been constructed as a four lane divided highway but the narrow grass median has since proven insufficient in preventing cross-directional collisions. In 1999, the Windsor-London stretch of Highway 401 was infamously dubbed as "Carnage Alley" after numerous fatal accidents. The most infamous was an 87 vehicle pileup on Labour Day weekend during thick fog that claimed seven lives and injured 40 others, just east of the Manning Road interchange and truck inspection centre. Due to this pile-up, the Ministry of Transportation began erecting signs that say "Fatigue Kills, Take A Break" and "Tailgating Kills, Leave Some Space" along the route between Windsor and London. These were later applied to other notoriously dangerous stretches of provincial highways across the province. Much of the construction work which is still ongoing involves replacing the median strip with an "Ontario tall-wall" concrete barrier and often an extra lane per direction.

Areas currently being upgraded are between Windsor and Tilbury, around the City of Kingston, the London area, from Stevenson Road in Oshawa to Highway 35/115, from Port Hope to Cobourg, and west from Cambridge towards Woodstock. This will be followed later by staged upgrades between Trenton and Belleville, and eventually the remaining sections between Cobourg and Kingston. Upgrading the final rural sections between Tilbury, Chatham and London, and from Cornwall to the Quebec Boundary remain beyond the 35-year planning horizon at this time.

As a result of multi-vehicle accidents that have shut down the freeway, the MTO implementated province-wide "Emergency Detour Routes" (labelled "EDR" along freeways and exits). These EDRs are signed at exits, and along parallel county roads (which may or may not have been downloaded/former provincial highways) or major arterial roads in towns and cities to help motorists detour around an accident and find their way back to the freeway if a stretch of it is closed for any reason. However, this diverts high speed highway traffic on to low speed country roads, creating congestion due to the reduced capacity of the road.

Windsor-area upgrades and extensions

On 14 November 2005, the joint Canadian-American committee studying the options for expanding the Windsor - Detroit border crossing announced that its preferred option was to directly extend Highway 401 westward, using a new bridge or tunnel to cross the Detroit River and interchange with Interstate 75 somewhere between the existing Ambassador Bridge span and Wyandotte.

In the 14 February 2008 issue of The Windsor Star, it was reported that the MTO was buying properties and making offers to buy other properties on the southwest side of Windsor for a potential extension of Highway 401. The area where the MTO is reportedly purchasing property is just south of E. C. Row Expressway, parallel to the existing freeway, where there is light development. Currently, the area is mostly rural, with a few newer houses with older ones as well, along with mostly-undeveloped parks and nature preserves (see Neighbourhoods of Windsor, Ontario#West Side for more information on this neighbourhood). Currently, the Ministry of Transportation has stated tentative plans for the extension of Highway 401 by travelling up Highway 3/Talbot Road/Huron Church Road, before branching west towards E.C. Row Expressway, heading towards the river towards a new bridge to Interstate 75. The cost for the access route/extension is estimated to be at $1.5 billion, but does not include expropriating homes and businesses along Highway 3 and in the "Yawkey Bush" neighbourhood. This plan follows the "GreenLink" proposal drafted up by the Detroit River International Crossing and the Windsor City Council.

Home owners along the newly-built Chappus Street subdivision have stated they are worried that their land values will weaken if they are sandwiched between E.C. Row and Highway 401, as their houses (and the extension of Chappus Street) were built around 2003, while area developer Ashraf Botros claims that his plans for a much larger subdivision around Chappus Street now have to be scuttled from this potential extension.

On March 3, 2008, the Michigan Department of Transportation and the MTO (in partnership with Transport Canada and 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, on both the American and Canadian sides to determine if the ground in the area was strong enough to support the weight of a proposed bridge over the river. The technical analysis had determined the soils along the river can indeed support the weight of a new bridge. This was a grave concern of all parties involved in the bridge construction process, due to the nearby Windsor Salt Mine's activities only a kilometer (0.6 mile) or so away, and the soils in the area being of clay and sandy sediment.

On May 1, 2008, it was announced that a new proposed highway, called the Windsor-Essex Parkway, will be connected extending Highway 401 to a new inspection plaza and river crossing in West Windsor. This project will cost about $1.6 billion, but the parkway will divert heavy trucks off local streets and there will be several tunnels so local residents can cross over the parkway with ease. There will be frontage roads for local traffic paralleling the parkway.

Essex County upgrades

The vast majority of the Essex County upgrades have been completed and opened to traffic. The only parts remaining to be upgraded are from 3 km west of Manning Road, to Highway 401's terminus in Windsor at Highway 3, which will be upgraded pending the approval of a new border crossing. This part of freeway has become a widened, concrete-paved six-lane freeway separated by an Ontario Tall-Wall barrier. Despite having a substantial increase in potential vehicle capacity, this section remains the newest and most lightly-travelled of any six-lane stretch of freeway in Ontario (as most freeways of more than six lanes are found in major urban areas, such as the Greater Toronto Area, London, Kitchener, and Ottawa).

Highway 3 to Essex County Road 19

The Windsor Star has reported that the stretch of Highway 401 from Highway 3 (its western terminus) to where the road widens to three lanes per direction (3 km west of Manning Road) will remain as a four-lane route until a route to a potential new border crossing has been finalized. The MTO intends on upgrading this section, particularly its dangerous interchange with Highway 3 (sharp curves, poor lines of sight, aging overpass structure) when a new bridge and freeway corridor has been chosen. The road widens from four lanes to six lanes just after approaching the former westbound truck inspection station.In the future, the city of Windsor has announced it will extend Highway 401 to the U.S. border where a bridge will be built and access to Interstate 75.

County Road 19 to County Road 42

Highway 401 is seeing a complete overhaul and expansion between the city of Windsor, Ontario and Tilbury, Ontario, in response to the 87-car pile-up that killed 8 on September 3, 1999. The road is being expanded from two lanes per direction with a narrow grass median to three lanes per direction (with concrete pavement), rumble strips, a concrete divider, and newer overpasses at Highway 77, French Line Road (St. Joachim Road), and two are planned for Puce Road, Belle River Road, and Former Rochester Township 3rd Concession Road (Eastern Lakeshore).

The next phase for upgrading and widening Highway 401 in Essex County is currently under way and will stretch from Belle River Road/Essex Road 27 to Highway 77, widening each carriageway from two to three lanes, with a concrete barrier, and should be completed by November 2007. This construction zone is roughly the same size as the previous two, at 10.6 km in length.

From (west) To (east)	Originally	Currently	Planned
3 km West of Manning Road to 1 km east of Belle River Road (County Road 27)	2 narrow lanes per direction, dangerously narrow carriageways, dangerously narrow median, bi-directional onramps	3 lanes per direction, Ontario Tall-Wall concrete barrier, separated onramps	Completed
1 km east of Belle River Road (CR 27) to 3 km west of Highway 77 interchange (10.6 km in length)	2 narrow lanes per direction, dangerously narrow carriageways, dangerously narrow median, bi-directional onramps	Under Construction/Widening/Upgrades	3 lanes per direction, Ontario Tall-Wall concrete barrier, separated onramps
3 km west of Highway 77 interchange to 1 km east of Queen's Line in Tilbury	2 narrow lanes per direction, dangerously narrow carriageways, dangerously narrow median, bi-directional onramps	3 lanes per direction, Ontario Tall-Wall concrete barrier, separated onramps	Completed

Additionally, the Windsor South Truck Inspection Station has been upgraded to a commercial vehicle inspection facility

London area upgrades

Highway 401 though the city of London, east of Wellington Road, had been widened to six lanes in the 1980s, using the median right-of-way and erecting a three-foot jersey concrete barrier. In the 1990s, the stretch east of London was also widened to six lanes all the way to just east of Highway 403, this time using a four-foot Ontario Tall-Wall concrete barrier. The Tall-Wall barrier was also added to the segment of Highway 401 from the west of Wellington Road until the overpass with Southminster Bourne, though this segment remained four lanes wide.

From 2006 to 2008, Highway 401 in London between Wellington Road and Highway 402 was widened from four to six lanes. The improvements included high mast lighting, a changeable message sign, advanced drainage systems and paved shoulders on both sides of the roadway. This, with the widening projects between Woodstock and Kitchener, made Highway 401 at least six lanes wide from Port Hope to the Highway 402 interchange (From London to Toronto).

The very busy Wellington Road interchange was completely redesigned and rebuilt as a parclo interchange. Construction began in 2006 and ended in mid 2008.

A parclo interchange with Wonderland Road west of the partial Highway 402 interchange will be completed to provide better connectivity for motorists in London's southwest end to access Highway 401 west to Windsor. No definite time line has been set for this project.

Long-term plans call for eight lanes through the city due to its increased use as a commuter road. However, these improvements are not planned until around 2020 and remain mid-to-long-term goals for the Ministry of Transportation.

Originally	Currently
Lanes: 4 from Highway 402 to Wellington Road.	Lanes: 6 from Highway 402 to Highway 403.
Median: Ontario Tall-Wall.	Median: Ontario Tall-Wall retained, with high-mast lighting poles and overhead sign gantries added at intervals.
Paved inner shoulder, gravel outer shoulder.	Paved inner and outer shoulders.
Rumble strips on outer shoulder	Rumble strips on both inner and outer shoulders.
Wellington Road overpass (1956) carries four lanes of local traffic, crossed six lanes of highway traffic.	Wellington Road overpass (2008) carries six lanes of local traffic, crosses up to ten lanes of highway traffic.
3/4 Cloverleaf interchange with Wellington Road.	Parclo A4 interchange with Wellington Road.

Oxford County upgrades

In the late fall 2005, the Ministry of Transportation of Ontario started a construction project to upgrade the current four-lane section of Highway 401 from four to six lanes from west of Oxford County Road 3 to west of Waterloo Regional Road 97 (where the next six-lane concrete-divided road begins) in the County of Oxford and Regional Municipality of Waterloo.

This is currently part of the last four-lane section between London and Toronto (stretching from Highway 403 Interchange in Woodstock, Ontario to Waterloo Road 97 in Kitchener, Ontario), but is being upgraded to six lanes plus an Ontario tall-wall barrier in the median. This is the first stage of upgrades of this final four-lane section.

In fall 2003, the widening of Highway 401 from four to six lanes from the Highway 8 interchange to Waterloo Regional Road 97 was completed. The Y-junctions with Highway 8 and Highway 403, opened in 1987 and 1990, respectively, were designed in mind to accommodate the widening of Highway 401 through Oxford and Waterloo.

Currently	Planned
Lanes: 4	Lanes: 6
Median: Grassed	Median: Ontario Tall-Wall
Rumble strips	Rumble strips (new)
Interchanges every 5 km or so	Interchanges every 5 km, plus two new emergency ramps
One slightly sharp curve north of Oxford Road (Oxford CR 29, Exit 250)	slightly re-aligned and straightened (completed and re-opened)

Aside from the addition of one lane per direction and a tall-wall barrier, two emergency ramp connectors that are intended to be used only during emergency highway closures, construction, and similar circumstances to permit traffic to move off the freeway (and emergency vehicles onto it) have been constructed. Built near Oxford Road 3 and Trussler Road, the ramps are an unprecedented addition to the Ontario highway system.

Other emergency accesses have been built in Essex County where the road was recently widened from 4 to 6 lanes, but these are gravel, and all are alongside overpasses, for use by ambulances, firetrucks, and police cars in emergencies only.

This is currently in stages, and will eventually close the 4-lane gap between the two 6-lane sections (London/Highway 402-Woodstock/Highway 403 and Kitchener/Waterloo Road 97 (Cedar Creek Drive)-Toronto).

The first segment in Oxford County to see the upgrades is from Waterloo RR 97 to Oxford CR 3, with further upgrades planned from Oxford CR 3 to Highway 403. Several large upgrades will be carried out here:

• The interchange of Towerline Road and Middletown Line (Exit 236, just north of Highway 403) has been completely rebuilt and redesigned, as its former ramp configuration was extremely dangerous (short ramps with tight curves leading from an intersection just 30 feet/10 meters from the freeway, requiring a driver to "floor it" to get up to speed in time).
• The aging and sagging overpass structure at Towerline Road has been replaced, making this a long-overdue upgrade.
• The cloverleaf interchange with Former Highway 2 (Exit 238, which was the final remaining cloverleaf with two divided highways in the province) is now converted into a parclo interchange, as cloverleafs are no longer up to the Ministry of Transportation's safety standards (mostly from weaving). This was not a disruptive construction contract, as the traffic volumes at the interchange (on Highway 2) were actually quite low (which is also why the cloverleaf interchange worked smoothly) since former Highway 2 has been all but replaced by Highway 403 in the early 1990s. This leaves the Highway 4/401 interchange in London, Highway 62/401 interchange in Belleville, and the former Highway 88/Highway 400 interchange in Bradford as the last cloverleaf interchanges on a 400-series highway.

Mississauga upgrades

There are plans to widen the Mississauga stretch from six lanes to 12 lanes from the 403-410 interchange to the Credit River, and 10 lanes to Mississauga Road; this has recently been a major bottleneck due to the reduced capacity west of the junction. Actual construction on the expansion is slated to start in 2008 at the earliest, but for the last decade, numerous prerequisite projects have been undertaken.

The 403-410 interchange, which was under construction from the 1970s until 1995, is designed in mind for westward expansion of the collector-express system. The Highway 401 collector overpass structures crossing Highway 410 each of which have an additional lane which is currently unused. There is also an available right-of-way for a loop ramp from Highway 403 northbound to Highway 401 west and a direction ramp in the opposite direction, which is designed to improve access from Cawthra Road; this project would make the 403-410 interchange a full four-way interchange.

The Kennedy Road overpass, opened in the early 1990s just west of the 403-410 junction, is wide enough to accommodate expansion of the 12 lane collector-express system. The Derry Road underpass have been widened to accommodate this in the late 1990s. An interchange has been added with Mavis Road in 1999, which has been extended north to Highway 401 and beyond, and the overpass abutments are designed to allow future lengthening so fourteen lanes can pass under. In 2002, the Mississauga Road four-lane overpass was replaced with an eight lane structure that can span fourteen lanes, while the interchange ramps were also realigned to support higher speeds.

The main obstacles to Highway 401 expansion are the aging Second Line, Creditview Road, and Hurontario Street overpasses, which were completed in the early 1960s and place height restrictions on vehicles passing under. They will be demolished and replaced as part of the reconstruction.

Recently, the Ministry of Transportation also has mid-term plans to construct HOV lanes along Highway 401 from Mississauga Road to the 403/410 interchange. They have also announced long-term plans to further extend the HOV lanes further west to Milton.

Durham Region area upgrades

Highway 401 in Durham Region between Stevenson Road and Highway 35/115 (approximately 23.4 km) has been resurfaced.

As this is the oldest stretch of freeway in use (having been constructed between 1938 and 1942), the road is seeing many upgrades, including the opening of new interchanges with longer ramps and better safety features, while older ones (such as the former Harwood Avenue interchange being replaced by the newly-built Salem Road interchange, 1 km to the east) have been closed off and removed.

The Park Road exit, Exit 416, has been replaced by a new interchange at Stevenson Road in Oshawa. Construction on the interchange began September 7, 2005. This project is set to be complete by 2010 at a total cost of $65,097,000.00..

Further west in Ajax, Highway 401 between Carruthers Creek and Church Street has been widened from four to five lanes. There are plans to widen the highway to 12 lanes with express-collector lanes extending from Brock Road in Pickering, to Brock Street in Whitby, along with interchanges at Lakeridge Road and the 407-401 Durham West Connector corridor towards Highway 407.

The Ministry of Transportation also has long-term plans to construct HOV lanes along Highway 401 from Brock Road in Pickering to Stevenson Road in Oshawa.

Traffic cameras

To manage traffic, the Ontario Ministry of Transportation (MTO) installed the Freeway Management System - COMPASS, the most advanced of its kind in the world when it was deployed in 1991 by Delcan Corporation. Using a combination of CCTV cameras, vehicle detection loops and LED changeable message signs, the MTO Traffic Operations Centre can obtain a real-time assessment of traffic conditions and alert highway travellers of collisions and construction. The system currently stretches from Highway 403, Mississauga to Harwood Avenue, Ajax, and is likely to be extended westward and eastward as Highway 401 is reconstructed and upgraded.

Volume Information (2005)

• Highest Volume AADT: 426,400 at Highway 400, Exit 359
• Highest Volume SAWDT: 498,700 at Highway 400, Exit 359.
• Lowest Volume AADT: 5,800 at Tunnel Route in Windsor

AADT = Average Annual Daily Traffic

SAWDT = Summer Average WeekDay Traffic

Major cities

Listed below are notable cities along the route of Highway 401, from west to east. Bolded cities are officially-designated control cities for signs. Windsor Chatham-Kent London Ingersoll Woodstock Kitchener-Waterloo Cambridge Guelph Milton Mississauga Toronto Pickering Ajax Whitby Oshawa Bowmanville Port Hope Cobourg Trenton Belleville Kingston Brockville Cornwall

Montréal is displayed as control city on signage east of Cornwall, although the nominal transition is far west of greater Montreal, at Rivière Beaudette.

Trivia

In the late 1980s to late 1990s, the stretch of Highway 401 eastbound around Milton and westbound around Whitby had chevrons painted in themiddle of each lane. Signs advised motorists to keep at least two chevrons apart, in essence warning them not to follow too closely. Some of these chevrons remain intact in the lanes in Whitby, although some of the signs stating their use have since been removed.

In 1986, the Canadian writer George Elliot published God's Big Acre: Life in 401 Country, a series of vignettes and portraits collected along the Windsor-Quebec corridor of the 401.

Until the late 1990s, Highway 401 had blue signs near Windsor and the Greater Toronto Area stating nearby Interstate highways in the United States as "Advantage: I-75 I-80 I-90". Advantage was Mainline Automated Clearance System that processed trucks electronically. Trucks were fitted with transponders that relayed location, date, time, weight and axle information. This allowed trucks to bypass truck inspection stations if they already have been inspected. It also improved processing times at truck inspection stations.

An example of the sign:

ADVANTAGE

Highway 401 is the busiest highway in North America, one of the busiest in the world, and one of the widest highways in the world, with a maximum of 18 through lanes. It has the longest collector/distributor configuration in the world

Incidents

In August 2005, the crash of Air France Flight 358 at Toronto Pearson International Airport was viewed by motorists traveling along Highway 401 near the airport. Traffic was highly congested throughout the day as emergency crews used the highway to access the crash scene. Many motorists also pulled over to witness the crash and its aftermath, affecting traffic flow for days. The international attention in the media often sidetracked to talk about the highway, noting its 18 lane collector/express configuration and its congestion. Traffic cameras along the 401 were also used to cover the event.

In August 2008, sections of the 401 in Toronto were closed during the 2008 Toronto Propane Explosion as a precautionary measure due to the highway's proximity to the blasts.

Exit list

The following are a few of the major interchanges:

Location	km	#	Destinations
Windsor	0.0		– Ambassador Bridge to USA
	2.6	13	Dougall Parkway – Detroit-Windsor Tunnel to USA
London	173.2	183
	179.1	189	Highbury Avenue – St. Thomas
Woodstock	225.3	235
Kitchener, Cambridge	267.9	278
Toronto	341.1	348 352
	348.9	359
	364.9	375
Pickering		399	Brock Road - To connect with the Temporary Eastern Terminus of Highway 407 ETR
Clarington	425.3	436
Leeds and the Thousand Islands	649.6	661	to USA
Edwardsburgh/Cardinal	708.6	721A

Bridges, overpasses and underpasses

There are a variety of overpasses used on the 401. Older spans were concrete bridges with copper railings. These overpasses have been replaced with either Box girder bridge or Girder bridge where the 401 has been widened.

In older sections of the 401 over rivers, Truss bridge are used to span across the waterway.

Service centres

The service centres are located at the following points on Highway 401 and contain the following services:

Location	km	Direction	Fuel	Food	Other
Ingersoll	223	Westbound	Esso	Tim Hortons, Wendy's	Nicholby's Express
	225	Eastbound	Esso	Tim Hortons, Wendy's	Nicholby's Express
Cambridge	289	Eastbound	Petro-Canada	McDonald's	Picnic Area
		Westbound	Petro-Canada	McDonald's	Picnic Area Ellis Chapel
Newtonville/Newcastle	444	Westbound	Esso	Tim Hortons, Wendy's	Nicholby's Express picnic area
Port Hope	453	Eastbound	Esso	Tim Hortons, Mr. Sub, Wendy's	Picnic area
Trenton	519	Eastbound	Petro-Canada	McDonald's - closed as of Oct 2009	Picnic area
		Westbound	Shell	Tim Hortons, Mr. Sub, Wendy's	Picnic area
Camden East	591	Westbound	Petro-Canada	McDonald's	Picnic area
Odessa	604	Eastbound	Esso - last fuel in Ontario as of Oct 2009	Tim Hortons, KFC	Picnic area
Mallorytown	677	Westbound	Esso	Tim Hortons, Wendy's	Picnic area
	679	Eastbound	Esso	Tim Hortons, Wendy's	Nicholby's Express
Lancaster	827	Westbound	Husky

Lane configuration from west to east

Section	Lane Configuration
Huron Church Road/Highway 3 to Essex County Road 42	2 lanes in each direction 1 additional lane in each direction currently under construction
Essex County Road 42 to Highway 402	2 lanes in each direction 1 lane in each direction currently planned.
Highway 402 to Oxford County Road 2	3 lanes in each direction 1 additional lane in each direction currently planned
Oxford County Road 2 to Oxford County Road 3	2 lanes in each direction 1 additional lane in each direction currently under construction
Oxford County Road 3 to Milton, ON	3 lanes in Each Direction
Milton, ON to Highway 410/Highway 403	3 Lanes in Each Direction Stretch east of Mississauga Road to 403/410 interchange currently being widened to accommodate a collector/express system 1 HOV lane per direction currently under planning
Highway 410/Highway 403 to Toronto Airport Basketweave	9 Lane collector/express system Eastbound 5 Express, 4 Collector 9 Lane collector/express system Westbound 4 Express, 5 Collector
Toronto Airport Basketweave to Highway 427/Eglinton Avenue	9 Lane collector/express system Eastbound 4 Express, 5 Collector 9 Lane collector/express system Westbound 4 Express, 5 Collector
Under the Highway 427 Interchange	4 lanes in each direction
Highway 427/Carlingview Drive to Highway 409	5 lanes in each direction
Highway 409 to Highway 400	7 lane collector/express system in each direction 4 Express, 3 Collector
Highway 400 to The Basketweave	9 lane collector/express system in each direction 4 Express, 5 Collector
The Basketweave to Allen Road	7 lane collector/express system in each direction 4 Express, 3 Collector
Allen Road to Don River West Branch Hogg's Hollow Bridge	7 lane collector/express system in each direction 3 Express, 4 Collector
Don River West Branch to Yonge Street	6 lane collector/express system in each direction 4 Express, 2 Collector 1 additional collector lane in each direction currently under construction
Yonge Street to Bayview Avenue	7 lane collector/express system in each direction 4 Express, 3 Collector
Bayview Avenue to Highway 404/Don Valley Parkway	7 lane collector/express system in each direction 3 Express, 4 Collector
Highway 404/Don Valley Parkway to Kennedy Road	8 lane collector/express system in each direction 4 Express, 4 Collector
Kennedy Road to Markham Road/Highway 48	7 lane collector/express system in each direction 3 Express, 4 Collector
Markham Road/Highway 48 to Neilson Road	6 lane collector/express system in each direction 3 Express, 3 Collector
Neilson Road to Whites Road (Durham Regional Road 38)	7 lane collector/express system in each direction 4 Express, 3 Collector
Whites Road to Brock Road (Durham Regional Road 1)	7 lane collector/express system in each direction 3 Express, 4 Collector
Brock Road to Westney Road (Durham Regional Road 31)	5 lanes in each direction 1 additional lane in each direction currently planned
Westney Road to Salem Road (Durham Regional Road 41)	5 lanes in each direction
Salem Road to Stevenson Road (Durham Regional Road 53)	3 lanes in each direction 2 additional lanes in each direction currently planned
Stevenson Road to Cobourg	3 lanes in each direction 1 additional lane in each direction currently planned
Cobourg to Frontenac County Road 38	2 lanes in each direction 1 additional lane in each direction currently planned.
Frontenac County Road 38 to Sydenham Road (Frontenac County Road 9)	3 lanes in each direction
Sydenham Road to Montreal Street (Frontenac County Road 11)	2 lanes in each direction 1 additional lane in each direction currently under construction
Montreal Street to Highway 15	2 lanes in each direction 1 additional lane in each direction currently planned
Highway 15 to Quebec Line	2 lanes in each direction

See also

• 400-series highways
• List of Ontario provincial highways
• Hogg's Hollow Bridge
• The Basketweave

References

1. [1]
2. [2]
3. Department of Highways, Ontario, Annual Report for the Fiscal Year Ending March 31st, 1942, p. 9
4. http://books.google.com/books?id=r0e-8PU_4dsC&dq=%22new+kingston+road%22+oshawa&q=%22highway+2s&pgis=1#search Annual Report By Ontario Dept. of Highways, Ontario Dept. of Agriculture and Food, Ontario Dept. of Public Works, 1940, 1941, 1949
5. TheKingsHighway.ca - History on Highway 401
6. Highway 401 - the Story.html
7. TheKingsHighway.ca - History on Highway 401
8. [3]
9. [4]
10. [5]
11. [6]
12. [7]
13. City News
14. CTV.ca
15. Hwy 401 - Page 3 - Ridgetown to London - Images
16. Border transportation partnership reaches milestone - March 3, 2008
17. The Windsor-Essex Parkway
18. Ministry of Transportation Road Construction Information
19. CKLW-AM 800
20. Government of Ontario, Canada - News
21. [8]
22. [9]
23. [10]
24. onthighways.com on the highways.com
25. Ministry of Transportation of Ontario, 2004 Annual Average Daily Traffic

External links

• Ontario Ministry of Transportation
• Live COMPASS 401 Traffic Cameras through the Greater Toronto Area
• Photographs of the Macdonald-Cartier Freeway (Highway 401)
• Highway 401 at OntHighways.com
• Highway 401 History at thekingshighway.ca
• Highway 401 - the Story
• Complete Highway 401 live traffic cams
• Truck Stops Within Ontario
• TravelCenters of America (operators of the Woodstock/Ingersoll Service Centers
• Highway Guide with Map and GPS Information. Section #1: Windsor to Toronto
• Highway Guide with Map and GPS Information. Section #2: Toronto to Quebec Border