Ontario Highway 5 History - The King's Highways of Ontario

King's Highway 5 is a major trunk highway which links the Greater Toronto Area with Hamilton and Paris. The highway passes through a predominantly urbanized area, with nearly two-thirds of the highway's length contained within built-up areas. The principal towns located along the highway are Toronto, Mississauga, Oakville, Burlington, Hamilton and Paris. The highway was first established in 1920 when the road from Cooksville (part of present-day Mississauga) to Hamilton and Port Dover was assumed as a provincial highway. The highway was extended from Cooksville to Toronto in 1921. In 1927, the section of Highway 5 from Clappison's Corners near Hamilton to Port Dover was renumbered as Highway 6. In turn, Highway 5 was extended westerly to meet up Highway 8 at Peters Corners. The highway was extended to St. George and Paris in the early 1930s. Highway 5 was almost lost entirely to downloading in 1998, when nearly 90% (or about 100 km) of this highway was transferred to municipalities. The only section of Highway 5 spared from the downloading was from the Highway 6 Junction at Clappison's Corners to the Highway 8 Junction at Peters Corners. The downloaded sections of Highway 5 retained their original route number after 1998, but they are now just municipal streets and county roads.

In 2012, the awkward "triple crossroads" intersection at Peters Corners was completely reconstructed. Highway 8 was realigned so that it met Highway 52 at a four-leg modern roundabout. The eastern leg of Former Highway 8 leading into Dundas was also realigned in order to separate it from the new roundabout. The new Peters Corners Roundabout was the very first multi-lane modern roundabout ever built on an Ontario provincial highway, and only the third roundabout completed on the provincial highway system. The new Peters Corners Roundabout was officially opened to traffic on October 4, 2012, although Eastbound Highway 8 traffic had been using a portion of the roundabout's circulatory roadway since September 15, 2012, due to construction staging. As a result of the highway realignment at Peters Corners, Highway 5 and Highway 8 are now signed concurrently for about 250 metres. This was done to connect the realigned route of Highway 8 coming from Cambridge with Former Highway 8 leading to Dundas.

The Ministry of Transportation (MTO) is also planning to replace the congested traffic signal at Clappison's Corners (Highway 6) with an interchange within the next few years. Highway 6 will be converted to a freeway through Clappison's Corners, and a new bridge will be constructed to carry Highway 5 over Highway 6. This project is now in design, although a proposed construction year has not yet been announced.

Highway 5 is a minimum of four lanes from Toronto to Clappison's Corners, except the section through Waterdown which is only two lanes. The balance of the highway from Clappison's Corners to Highway 2 in Paris is two lanes. The former concurrent route of Highway 5 and Highway 24 between St. George and Osborne Corners is no longer signed. Services along Highway 5 are generally quite plentiful. The speed limit on Highway 5 is 80 km/h (50 mph), unless posted otherwise. Please visit the Highway 5 Mileage Chart page for a list of mileage reference points along Highway 5.