Section 900 Of Chapter 1. General Provisions From California Streets And Highways Code >> Division 2. >> Chapter 1.

. The authority conferred upon boards of supervisors by this division shall be exercised subject to such limitations and restrictions as are prescribed by this division or by other provisions of law, shall be in addition to any authority elsewhere conferred, and, except as otherwise expressly provided, shall be exercised only in relation to highways within their respective counties.