Utility facilities occupy State highway rights-of-way as provided by law, or pursuant to permission of the department. Utility occupation, whether by legislated right or by permission is subordinate and subject to the use of the rights-of-way by the department for highway or other uses authorized by law. It is in the public interest for utility facilities to be accommodated within the highway rights-of-way when such use and occupancy does not interfere with the free and safe flow of traffic, otherwise impair the highway or conflict with the use of the rights-of-way by the department, including, but not limited to walkways, bikeways, and scenic areas. Utility occupation is subject to all applicable laws, regulations of other agencies with jurisdiction thereover, regulations of this department in this Part and other Parts of its regulations, and conditions imposed by the department. This Part is applicable to all utility installations, modifications, relocations, maintenance, operations and repairs within State highway rights-of-way.