Tex. Transportation Code § 252.105

(a) A road commissioner controls the overseers, laborers, tools, machinery, and vehicles to be used on the roads in the road commissioner's district and may require overseers to deploy laborers that the road commissioner designates to open, work on, or repair roads or to build or repair bridges or culverts in the district.

(b) A road commissioner shall:

(1) ensure that the roads and bridges in the district are kept in good repair;

(2) under the control of the commissioners court, establish a system of grading and draining public roads in the district and ensure that the system is carried out by the overseers and laborers under the road commissioner's control;

(3) under the direction of the commissioners court, spend the money entrusted to the road commissioner by the court in the most economical and advantageous manner on the public roads, bridges, and culverts of the district; and

(4) put the inmates and other laborers furnished by the commissioners court to work.

(c) A road commissioner is responsible for the safekeeping of and is liable for the loss or destruction of the machinery, tools, or vehicles placed under the road commissioner's control unless the road commissioner was not at fault. When discharged, the road commissioner shall deliver those items to the person designated by the commissioners court.

(d) Inmates may not be required to work when there is available, after building and repairing bridges, a sufficient road fund to provide for the necessary work on the roads.