returns id of this trip . concode_field_sep List<List<Street>> trace concode_elem_sep String tripId concode_elem_sep List<Stop> stops concode_elem_sep List<LocalTime> stopTimes concode_field_sep List<List<Street>> getTraces concode_elem_sep List<LocalTime> getStopTimes concode_elem_sep String toString concode_elem_sep LocalTime getStartingTime
String function ( ) { return tripId ; }