No person shall wilfully interrupt or molest the city engineer while engaged in his official duties by riding or driving any animal or vehicle of any kind against the person or surveying instruments or tools of the city engineer or any of the assistants or employees of the city, or by moving or displacing any stake or other landmark fixed, set or determined by the city engineer or any of his assistants or employees, or by driving over any pavement or street which the city engineer shall deem advisable to close, while the same are being improved, paved or repaired, or by wilfully causing or offering the city engineer or any of his assistants or employees any kind of corporal injury or hindrance or by impeding their work or progress in any other way. The city engineer or any of his assistants or employees, while engaged in necessary work for the city, shall have the right to call upon any policeman of the city to clear and keep clear any street where they may be working, of all animals, vehicles or obstructions of any description while such work is in progress. (Code 1953, § 2.22)