(1) The state trunk line highway system of this state consists of all roads, streets, and highways, either located within or outside the limits of incorporated cities and villages, now or hereafter constituted state trunk line highways under the laws of this state. The director of the department may establish subordinate classifications or groupings of state trunk line highways as the department deems necessary or desirable for proper administration of the state trunk line highway system. Additions to and deletions from the state trunk line highway system may be made in the manner prescribed by law. All roads, streets, and highways included in the state trunk line highway system shall be known and may be referred to for all purposes as state trunk line highways.

  (2) The department or a local road agency may enter into an operating license agreement with a regional transit authority to operate a public transit system on the streets and highways of this state as provided for in state law enacted after January 1, 2012. As part of such an agreement, the department or local road agency may designate 1 or more lanes of a street or highway as a dedicated public transit lane. A dedicated public transit lane may be reserved for the exclusive use of public transit vehicles operated by a regional transit authority during periods determined by the department or the local road agency, except that a dedicated public transit lane shall be made available at all times to emergency services vehicles. Lanes designated and marked as dedicated public transit lanes by the department or a local road agency under an operating license agreement with a regional transit authority are subject to the same provisions as high-occupancy vehicle lanes under the Michigan vehicle code, 1949 PA 300, MCL 257.1 to 257.923.