901.05  WARNING LIGHTS.
   Any person engaged in or employing others in excavating or otherwise in any manner obstructing a portion or all of any street, sidewalk, alley or other public way shall, at all times during the night season, cause at least two illuminated red lamps to be securely and conspicuously posted on, at or near each end of such obstruction or excavation. If the space involved exceeds fifty feet in length, then at least one additional lamp for each additional fifty feet or portion thereof excavated or obstructed shall be posted. (1964 Code §50.05)