What is Involved in Constructing a Four Lane Highway?

The process begins when MTO officials determine that a highway will soon be unable to efficiently handle the number of vehicles using it.

Planning is comprehensive. A route that is technically sound and minimizes impacts to the environment and affected property owners is selected after extensive public consultation.

The MTO recognizes the need to manage Ontario's forests, lakes, rivers, and wildlife resources responsibly. Plans for proposed four laning undergo a comprehensive environmental assessment process prior to approval, a process that can take two to three years to complete.

Often, four-laning is undertaken by twinning the existing highway. This involves constructing a new road parallel to the existing two lane roadway and dividing northbound and southbound traffic with the use of a median.

In urban or built-up areas, or in areas with significant environmental impacts, twining may not be possible. In those situations, both northbound and southbound lanes are constructed on a new alignment to minimize these impacts.

Once the route selection planning process is complete, a variety of engineering activities must take place. The proposed highway corridor and service roads are carefully surveyed. Geotechnical testing determines if the existing soils can support the highway and bridges. The roadway and bridges are designed. Finally, property required for the construction of the highway is purchased.

Proposed highway improvements are divided into projects to facilitate planning, design, and construction. After environmental approvals from the planning phase are received, another three to four years are required to complete the engineering process and the acquisition of property. Finally, each project takes, on average, three years to build.