(a) A port-of-entry supervisor, an inspector employed by the Alcoholic Beverage Commission, or a weight enforcement officer who has reason to believe that the axle or gross weight of a loaded motor vehicle is unlawful may weigh the vehicle using portable or stationary scales furnished or approved by the Department of Public Safety.
(b) If the vehicle exceeds the maximum gross weight authorized by law, plus the tolerance allowance provided by Section 621.403, the supervisor, inspector, or weight enforcement officer may prohibit the vehicle from proceeding farther into the state.