The Public Transportation and Highway Improvement Act (PTHIA) sets forth the regulations concerning roads that are under the authority of the Province of Ontario. The act distinguishes and sets out the applicability of the HTA to provincial highways, which are designated as part of The King's Highway (primary), a secondary highway, or a tertiary road. Tertiary roads may also be designated as a resource road, allowing for vehicles otherwise prohibited from public roads. Industrial roads are privately owned routes with which the MTO has entered an agreement to improve or allow public access, and are not considered part of the provincial highway network.