No person or government agency shall operate any train in a manner as to prevent vehicular use of any highway for a period of time in excess of fifteen (15) consecutive minutes except:
(1) When necessary to comply with signals affecting the safety of the movement of trains;
(2) When necessary to avoid striking any object or person on the track;
(3) When the train is stopped to comply with a governmental safety regulation;
(4) When the train is disabled;
(5) When the train is in motion except while engaged in switching operations;
(6) When there is no vehicular traffic waiting to use the crossing.