California Code, Streets and Highways Code - SHC § 36062

The tax need not be imposed on different classes, established pursuant to Chapter 3 (commencing with Section 36040) of the business on the same basis or at the same rate;  provided, however, that the tax imposed for the purpose of the acquisition, construction or maintenance of parking facilities for the benefit of the area shall be imposed on the basis of benefit determined by the city council after giving consideration to the total cost to be recovered from the businesses upon which the tax is to be imposed, the total area within the boundaries of the parking and business improvement area, the assessed value of the land and improvements within the area, the total business volume generated within the area, and such other factors as the city council may find and determine to be a reasonable measure of such benefit.