Ontario Highway 401 History - The King's Highways of Ontario

King's Highway 401 is the primary through route across Southern, Central and Eastern Ontario. Since the highway's completion in the late 1960s, Highway 401 has evolved from being a convenient bypass to a vital economic corridor. Today, the highway is used by millions of motorists to travel across the province quickly. It is also used by thousands of transport trucks every day, carrying goods to and from Ontario manufacturers and consumers. The economic activity generated by Highway 401 is immeasurable. This highway has contributed greatly to Ontario's prosperity in recent decades. One section of Highway 401 in Toronto between Weston Road and Highway 400 now carries over 420,000 vehicles on an average day, giving Highway 401 the distinction of being North America's busiest highway.

The need for a new east-west highway across Ontario was first recognized in the 1930s, when congestion started to become a problem in towns and cities along Highway 2. Before the days of Highway 401, all through traffic had to use Highway 2, which was a standard two-lane highway that passed right through every town along its route from Windsor to the Quebec Boundary. Planning for a new four-lane highway began before World War II, but the first section of the new highway was not completed until 1947. This new highway ran from West Hill in Scarborough Township to Oshawa and was known initially as Highway 2A. The route number was changed from Highway 2A to Highway 401 in 1952, when 400-series highway numbering was first introduced. The most important link in Highway 401 was the Toronto Bypass. This critical section of the new highway ran just to the north of the urbanized area of Toronto. The Toronto Bypass was completed in 1956 after several years of construction. It ran from Highway 27 to West Hill, located in Scarborough Township. The rest of Highway 401 was completed across Ontario in multiple phases, with the highest priority given to those sections where traffic congestion on neighbouring highways was a problem. The high priority sections included the Windsor to Tilbury section, the London to Woodstock section, the Milton to Toronto section, the Oshawa to Port Hope section, the Trenton to Belleville section and the Kingston to Gananoque section. The remaining phases of Highway 401 were completed later, during the 1960s. Eventually, a new four-lane highway had been completed from the Oshawa area easterly to the Quebec Boundary, and from Toronto southwesterly to Windsor. The final section of Highway 401 was completed between Gananoque and Brockville in 1968, completing an 818 km controlled-access freeway across the southern half of Ontario. The highway was officially rededicated as the Macdonald-Cartier Freeway in 1965, to commemorate two of Canada's Fathers of Confederation, Sir John A. Macdonald and Sir George Etienne Cartier. Special commemorative highway signs, like the example seen above, used to greet motorists at every entrance to the highway. After a decade of government cost-cutting, the blue signs were deemed to be expendable and were quickly phased out in the 1990s. The last Macdonald-Cartier Freeway sign was removed from Hwy 401 near Pearson International Airport in 2014.

Initially, the entire highway was four lanes, with two lanes for each direction of travel. By the late 1950s, congestion was becoming a serious problem on Highway 401 across Toronto. The Toronto Bypass was widened to a minimum of twelve lanes (six lanes per direction) from Islington Avenue to Neilson Road during the 1960s and early 1970s. This project included the introduction of a collector-express lane configuration, in order to separate local traffic from through traffic. With the new collector-express lane configuration, motorists could only enter or exit the highway from the collector lanes. There was no direct interchange access from the express lanes to intersecting roads, except at a handful of freeway interchanges. Motorists wishing to switch between the express and collector lanes could utilize one of the transfer roads. These transfer roads joined the collector and express lanes together at strategic intervals along Highway 401. In 1985, another multi-lane collector-express section of Highway 401 was completed between Highway 427 and Highway 403 in Mississauga, boasting eighteen though lanes (nine lanes for each direction). The most ambitious recent collector-express lane construction project on Highway 401 was between Neilson Road and Brock Road. This massive reconstruction project was completed in 1997 and provided a minimum of twelve lanes (six lanes in each direction) along Highway 401 between Scarborough and Pickering. An extension of the collector-express lanes in Mississauga through the Hurontario Street Interchange began in 2009 and was officially commissioned on October 30, 2013. The widening of Highway 401 from Hurontario Street to the Credit River began in mid-2016 and is scheduled for completion in 2020. The extension of the collector-express lanes from the Credit River westerly to Winston Churchill Boulevard and from Highway 407 to Milton is now in the construction phase, with some preliminary work underway as of July, 2019. More significant construction work began along this 18 km section towards the end of 2019. This $640-million highway expansion is being undertaken as a Public-Private Partnership between the province and the private sector (West Corridor Constructors). Expansion of Highway 401 between Highway 25 in Milton and the Credit River was completed in December 2022.

Many other sections of Highway 401 have been widened to six lanes since the 1970s. The entire route of Highway 401 from the western end of Mississauga to Kitchener was widened to six lanes during the 1980s and early 1990s. The highway was also widened to six lanes from London to Woodstock during the early 1990s and from Kitchener to Highway 97 (Cedar Creek Road) between 2000 and 2003. Highway 401 was widened to six lanes through Ajax, Whitby, Oshawa and Bowmanville in the 1970s and early 1980s. Since 2004, Highway 401 from Windsor to Tilbury have been widened to six lanes. The Ministry of Transportation (MTO) completed reconstruction and widening of the last remaining four-lane section of Highway 401 in the Windsor area to six lanes in 2010. The MTO also completed the widening of the final four-lane section of Highway 401 from Woodstock to Highway 97 (Cedar Creek Road) in early 2011. The existing six-lane section of Highway 401 between the Highway 8 Interchange and Highway 24 Interchange in Cambridge is now scheduled for widening to ten lanes. This project began in 2015 and is tentatively scheduled for completion by the end of 2018. Since the late 1990s, Highway 401 has been widened to six lanes from the Highway 35 & Highway 115 Interchange near Bowmanville to the Burnham Street Interchange in Cobourg. Widening of Highway 401 from four to six lanes from Burnham Street to beyond Nagle Road near Cobourg began in 2015 and was completed by late 2017. Widening of the Kingston Bypass to six lanes began in 2005 and was completed between Highway 38 and Montreal Street in 2012. Widening of the last section of the Kingston Bypass, from Montreal Street to the Highway 15 Interchange, is expected to be completed by 2016. Improvements have also been made to the section of Highway 401 from Brock Road in Pickering to Salem Road in Ajax, where a total of ten through lanes (5 per direction) have been provided.

In January 2005, the Detroit River International Crossing (DRIC) study team embarked on a multi-year study to investigate potential border crossing improvement options between Windsor and Detroit. The study sought to address the capacity problems associated with the two existing crossings at the Ambassador Bridge and the Detroit-Windsor Tunnel. Until recently, all traffic from Highway 401 was deposited onto municipally-maintained surface streets (specifically Huron Church Road and Dougall Avenue) about 11 km south of the two existing crossings. Serious traffic congestion occurred on the streets approaching the Detroit-Windsor Tunnel and the Ambassador Bridge, as through traffic mixed with local city traffic. Studies have been done to investigate different construction options, including the improvements of the two existing crossings. On May 1, 2008, the DRIC study team announced that a preferred alternative had been selected. Plans for the new Windsor-Essex Parkway were unveiled. This new 11 km freeway was essentially a westerly extension of Highway 401.

Environmental assessment approvals were received in 2009 and the property acquisition phase began shortly thereafter. The construction contracts for the first phase of the Windsor-Essex Parkway got underway in December 2009. The new Windsor-Essex Parkway began where Highway 401 previously ended at the Highway 3 Interchange in Windsor. The new freeway then proceeded to the site of a proposed new international bridge between LaSalle and the current Ambassador Bridge. The Windsor-Essex Parkway was constructed as a six-lane fully controlled access freeway, with interchanges at all major crossing roads. Most of the Windsor-Essex Parkway will be built below-grade. A series of 11 tunnels, totalling 1.8 km in length, were built so that international traffic would not interfere with local traffic and pedestrian movements. The Windsor-Essex Parkway generally followed the route of Talbot Road and Huron Church Road from the current terminus of Highway 401 to the E.C. Row Expressway, where the new Parkway diverged from Huron Church Road and headed due west towards the proposed international bridge site near LaSalle. The diversion of truck traffic onto the new Windsor-Essex Parkway resulted in a more pleasant environment along local Windsor streets, which have long been overburdened with international traffic. On November 28, 2012, the Ontario Government announced that the Windsor-Essex Parkway would be dedicated to the Rt. Hon. Herb Gray, a well-known and long-serving member of parliament representing the Windsor area. Since 2012, the Windsor-Essex Parkway has been officially known as the Rt. Hon. Herb Gray Parkway. This parkway is essentially an extension of Highway 401. The easternmost 8 km of the highway between Highway 3 and the E.C. Row Expressway officially opened to traffic on June 29, 2015, while the balance of the 11 km highway from the E.C. Row Expressway to the proposed international bridge site opened to traffic on November 21, 2015. This event was be historically significant, as it marked the true completion of Ontario's famous transprovincial freeway, Highway 401. The Windsor Extension of Highway 401 cost $1.4 billion over four years and created 12,000 construction jobs. The last time a new section of Highway 401 opened was in the Brockville area in October, 1968.

On August 24, 2007, Transportation Minister Donna Cansfield announced that Highway 401 from Trenton to Toronto would be dedicated as the "Highway of Heroes". The intent of this new designation is to commemorate Canada's fallen soldiers who died while serving in Afghanistan. This section of Highway 401 has witnessed several repatriation ceremonies over the years and it is hoped that the new highway designation will encourage Canadians to reflect upon the sacrifices that our Armed Forces have made while serving in Afghanistan. New highway signs bearing a large red poppy and the commemorative Highway of Heroes designation were installed along Highway 401 between Toronto and Trenton in September, 2007. The Highway of Heroes designation was extended westerly from its previous western terminus at the Highway 404 & Don Valley Parkway Interchange to the Keele Street Interchange on September 18, 2013. The extension of the highway designation was a result of the relocation of the Forensic Sciences Centre from Downtown Toronto to the Downsview Government Complex.

There are 19 Service Centres located along Highway 401. These centres are open 24 hours a day and offer motorists convenient access to fuel, restaurants and picnic areas. The centres are located about every 80 km (50 miles) except through the Greater Toronto Area, where services are generally available at almost every interchange. The posted speed limit on Highway 401 is 100 km/h (60 mph). However, an increased speed limit of 110 km/h (70 mph) was introduced on a section of the highway between Windsor and Tilbury, effective April 22, 2022. Exits along Highway 401 are numbered based on their distance from the Ambassador Bridge in Windsor. Approximate distances along the highway can therefore be calculated by subtracting one exit number from another. For example, the distance from Highway 404 (Exit 375) to Highway 37 (Exit 544) is 169 km (544 - 375 = 169). Please visit the Highway 401 Mileage Chart page for a list of interchange numbers along Highway 401.