(a) The following are ex officio directors of a road district established under this subchapter:
(1) for a county that is wholly included in the district, the county judge and each county commissioner; and
(2) for a county only part of which is included in the district, the county judge and the county commissioner of each commissioner precinct included in whole or part in the district.
(b) The ex officio directors have the same power and authority in the management of the affairs of the road district as the commissioners court of a county has in a road district located entirely in the county.