California Code, Vehicle Code - VEH § 11114

The department may require any person licensed under this chapter to submit to a reexamination of his qualifications when there is reasonable cause to believe that the licensee does not have the ability to give driving instruction. If the licensee refuses or fails to submit to such reexamination, the department may peremptorily suspend his license until such time as the licensee shall have submitted to reexamination. The suspension shall be effective upon notice.