Texas Transportation Code - TRANSP § 551.303. Operation on Roadways

(a) A neighborhood electric vehicle may be operated only on a street or highway for which the posted speed limit is 45 miles per hour or less.  A neighborhood electric vehicle may cross a road or street at an intersection where the road or street has a posted speed limit of more than 45 miles per hour.  A neighborhood electric vehicle may not be operated on a street or highway at a speed that exceeds the lesser of:

(b) A county or municipality may prohibit the operation of a neighborhood electric vehicle on a street or highway if the governing body of the county or municipality determines that the prohibition is necessary in the interest of safety.

(c) The Texas Department of Transportation may prohibit the operation of a neighborhood electric vehicle on a highway if that department determines that the prohibition is necessary in the interest of safety.