Any county, city or permanent road division, within the limits of which there is a State highway, may do or order to be done on any such highway any paving, curbing, highway work or sewer work authorized by law. Such governmental unit shall first obtain from the department a permit to do any such work. All grades, elevations or curb lines sought to be established or pavement proposed to be constructed by any such governmental unit shall first be approved by the department. Such governmental unit shall restore, to the satisfaction of the department, any existing pavement which is damaged as a result of such work.
Ca. Sts. and High. Code § 810