Streets and Highways Code § 27146
CHAPTER 8. Organization and Powers of the Board and the Executive Officers
For the purpose of considering questions relating to the bridge and highway district generally or local questions affecting a particular county or group of counties, the board or any of its committees may hold meetings in the chambers of the boards of supervisors of any county in the group, if suitable for that purpose, or at any other suitable place which the board or any of its committees may designate.