In Abrams v. State, 563 S.W.2d 610 (Tex. Crim. App. 1978), the court of criminal appeals considered the validity of a city ordinance that created the offense of speeding where the offense was defined as driving at a rate of speed greater than thirty miles per hour unless otherwise posted. Id. at 613. The court noted the Texas Legislature had enacted an offense that defined speeding as driving a vehicle at a "speed greater that is reasonable and prudent under the circumstances then existing . . ." Id. Because the ordinance defined an offense by way of a rigid speed limit, it conflicted with the state law defining speeding in a different manner. Id. at 615. The court held the ordinance to be void because of this conflict. Id.