(a) If the department inspects a bridge under the jurisdiction of a county or a municipality and determines that the bridge qualifies for a lower load rating under 23 C.F.R. part 650, Subpart C, than is currently permitted, the department shall notify the commissioners court of the county or the governing body of the municipality.
(b) A commissioners court or governing body that is notified under Subsection (a) shall post notices on the road or highway approaching the bridge that state the maximum load permitted on the bridge. The notices must be posted at locations that enable affected drivers to detour to avoid the restricted bridge.

(c) The department may post a notice required under Subsection (b) for a bridge under the jurisdiction of a county or a municipality if the department is required or authorized under federal law to post the notice. The notice must be posted in accordance with federal law.