(A)   The City Council may prescribe routes through the city for the use of trucks in general, trucks of particular kinds and/or other vehicles which are not ordinary private passenger vehicles, passing through the city.  Appropriate and adequate signs shall be placed along such routes so that drivers of such vehicles may follow the routes.
   (B)   When such signs are so erected and in place, the driver of a truck or other vehicle for which a route has been prescribed, as provided above, while passing through the city, shall keep on such route and shall not deviate therefrom except in case of emergency.  Drivers of such vehicles shall follow such routes so far as practicable also when driving within the city and not merely through the city.
(`83 Code, § 15-543)  Penalty, see § 71.999