Cal. Sts. & High. Code § 1050

For the purposes of this chapter, “private byroads” are roads opened, laid out, or altered for the purpose of providing access to parcels of contiguous private land of more than 100 acres which have been cut off by a change in the course of a navigable stream. Except as provided in this chapter, private byroads may be opened, laid out, or altered for the necessity of one or more residents or landowners of any road district in the same manner, and using the same procedure, as specified for the opening, laying out, or altering of public roads as provided in Article 3 (commencing with Section 1160) of Chapter 4; provided, however, that only one petitioner is necessary.