California Code, Vehicle Code - VEH § 12804.10

(a) Notwithstanding any other provision of law, a person issued a class C license under paragraph (3) of subdivision (b) of Section 12804.9 may drive any house car of 40 feet in length or less without obtaining a noncommercial class B driver's license with house car endorsement as described in subdivision (b).

(b) Any person seeking to drive any house car over 40 feet in length, excluding safety devices and safety bumpers, shall obtain a noncommercial class B driver's license with house car endorsement as described in this subdivision. The applicant for that endorsement shall pass a specialized written examination and demonstrate the ability to exercise ordinary and reasonable control in operating that vehicle by driving it under the supervision of an examining officer. Upon satisfactory completion of the examination and demonstration, the applicant shall be issued a noncommercial class B driver's license with house car endorsement by the department. Upon application for an endorsement to operate this vehicle, and every two years thereafter, the applicant shall submit medical information on a form approved by the department.