In lieu of reimbursement for transportation expenses for travel within San Mateo County, the City and County of San Francisco, Alameda County, Contra Costa County and Santa Clara County, members of the Board of Supervisors and the County Manager may elect to receive a maximum biweekly transportation allowance in the amount of $513 or as is currently set by the Board of Supervisors. Department heads, elected officials, and certain management employees designated by the County Manager may elect to receive such a transportation allowance in a maximum biweekly amount not to exceed $513 dependent on usage and approval by the County Manager.