The purpose of the Ontario Environmental Assessment Act is to help protect and conserve Ontario 's environment by ensuring that projects subject to the Ontario Environmental Assessment Act follow a planning process leading to environmentally sound decision-making.

The Ontario Ministry of Transportation’s Class Environmental Assessment for Provincial Transportation Facilities (2000) outlines the Environmental Assessment process to be followed for specific groups of provincial transportation projects. The Class Environmental Assessment is approved under the Act and provides a streamlined process which projects or activities within a defined “class” must follow. Provided that this process is followed, projects and activities included under the Class Environmental Assessment does not require formal review and approval under the Ontario Environmental Assessment Act.

Project groupings within the Class Environmental Assessment have been established as follows:

• Group "A" - Projects involving new facilities
• Group "B" - Projects involving major improvements to existing facilities
• Group "C" - Projects involving minor improvements to existing facilities
• Group “D” - Activities that involve operation, maintenance, administration and miscellaneous wok for provincial transportation facilities

For Projects subject to the Class Environmental Assessment, an environmental assessment involves identifying and planning for environmental issues and effects prior to implementing a project. The process allows reasonable opportunities for public involvement in the decision-making process of the project.

Other aspects of the environmental assessment process applicable to these project types are contained in the Class Environmental Assessment for Provincial Transportation Facilities (2000). Readers interested in these matters are encouraged to refer to that document.