U.S. Highways in Texas are owned and maintained by the state. These U.S. Highways are the second-highest category of road classifications in the Texas road system, just below the Interstate Highways. U.S. Highways are marked with a number contained inside a white shield in a black box. The number is generally even if the highway runs eastâÂÂwest, and generally odd if it runs northâÂÂsouth, though there are many substantial deviations from this plan.