Cal. Gov. Code § 8687.8
If the local agency, under Section 8687.4, is a county, the director, in determining whether the county's financial resources are exhausted, shall ascertain whether the county has levied, during the then current year (the year of the disaster), the maximum property tax for highway purposes authorized by Section 1550 of the Streets and Highways Code in the road district in which the work is proposed, and if such tax is being levied at less than the maximum rate authorized by Section 1550, the amount to be allocated by the director under this section shall be reduced by an amount equivalent to the difference between the revenue derived from the property tax being levied for highway purposes in such road district and the revenue which would have been derived from such tax at the maximum rate authorized by Section 1550. In determining if a county has levied sufficient taxes, amounts to be received from other taxes levied by that county and used for road purposes shall be included.
Ca. Gov. Code § 8687.8