All law enforcement agencies shall, not later than January 1, 1991, establish a policy and issue an order, in writing, which states whether or not their officers are required to wear seat belts. When a law enforcement agency is developing a safety belt policy, the agency shall consider the officer’s safety, comfort, and convenience.
Source:
Section 27315.5, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=27315.5..