GOV § 26613

Notwithstanding the provisions of Section 29601 the board of supervisors in a county having a population in excess of 3,000,000 may authorize the sheriff to enforce the provisions of the Vehicle Code in the unincorporated area of such county but only upon county highways. The expense incurred by the sheriff in the performance of such duties shall be a proper county charge.

The sheriff shall, on or before the fifth day of each month, forward to the Department of the California Highway Patrol copies of all accident reports made to the sheriff’s office and all accident reports of accidents investigated by the sheriff’s office.