Tex. Transp. Code § 251.1575
(a) A commissioners court may identify an alternate route to a road and require heavy vehicles having a gross weight of more than 60,000 pounds to travel the alternate route in order to prevent excessive damage to the road due to the volume of traffic by such heavy vehicles. An alternate route identified under this subsection must be:
(c) A person who is required to operate or move a vehicle or other object on an alternate route identified under this section is not liable for damage sustained by the road, including a bridge, as a result of the operation or movement of the vehicle or other object, unless the act, error, or omission resulting in the damage constitutes:
Added by Acts 2013, 83rd Leg., R.S., Ch. 1019 (H.B. 2612), Sec. 3, eff. June 14, 2013.