Texas Transportation Code - TRANSP § 257.117. Levy of Bond Tax

(a) Each year, the commissioners courts of the counties included in whole or part in a road district established under this subchapter shall determine the amount of the district bond tax to be imposed.

(b) The commissioners court of each county shall impose the portion of the bond tax imposed by the road district in that county at the time and in the manner that other taxes are imposed in the county by the commissioners court of the county.  The imposition of the tax is governed by the law governing the imposition of county taxes.