It is the general duty of the city transportation engineer to determine the installation and proper timing and maintenance of traffic control devices, to conduct engineering analyses of traffic accidents and to devise remedial measures, to conduct engineering investigations of traffic conditions and to cooperate with other city officials in the development of ways and means to improve traffic conditions, and to carry out the additional powers and duties imposed by ordinances of the city and as directed by the mayor. (Prior code title 46, art. 2 § 69)