What is the route with the least amount of traffic from Baltimore to Washington , DC during the average PM rush hour
O O O O O O O O O B-SL_OBSTRUCTION_AVOID O B-SL_SOURCE O B-SL_DESTINATION I-SL_DESTINATION I-SL_DESTINATION B-SL_DATE_TIME_DEPARTURE I-SL_DATE_TIME_DEPARTURE I-SL_DATE_TIME_DEPARTURE I-SL_DATE_TIME_DEPARTURE I-SL_DATE_TIME_DEPARTURE I-SL_DATE_TIME_DEPARTURE