Agency-Initiated Bus Noise Reductions for the Los Angeles Metro Orange Line

This paper presents noise control efforts of the Los Angeles County Metro Orange Line, one of the first 3 bus rapid transit (BRT) systems in the U.S. through residential areas. The Orange Line is a 14-mile (22.5 4 km) dedicated BRT corridor in the San Fernando Valley in Los Angeles County that utilizes 60-foot (18.3 5 m), articulated vehicles powered by compressed natural gas engines. Noise control efforts included noise 6 mitigation design features, establishing noise emission values of the buses, modeling of the operational 7 noise to determine location where residual impacts occur, establishing background noise levels, 8 monitoring operational noise levels, mitigation of residual noise impacts, and retrofitting the fleet with 9 new mufflers. The paper discusses the results of an agencies commitment to resolving community 10 environmental noise issues and provides guidance regarding noise modeling and noise specification of 11 city buses.