FMVSS 141 for Commercial Vehicles: Applicability and Limitations

Newly manufactured light-duty hybrid and electric passenger vehicles must comply with FMVSS 141 minimum sound requirements to reduce the risk of crashes with visually impaired and inattentive pedestrians. Commercial vehicles operate in a variety of noise-critical environments, from densely packed industrial yards to congested urban areas, making safe electric vehicle operation around pedestrians and bystanders vital. Though the market share of medium and heavy-duty hybrid and electric vehicles is projected to increase annually, there are currently no North American regulations specifically for minimum sound emissions of hybrid and electric vehicles heavier than 10,000 lb. GVWR. The primary intent of this paper is to investigate the efficacy and limitations of the current FMVSS 141 requirements when applied to heavy-duty electric trucks. Serving as a complementary test case, a Class 8 Freightliner eCascadia electric truck with onboard Acoustic Vehicle Alerting System (AVAS) was evaluated at Daimler Truck North America’s High Desert Proving Grounds in accordance with the FMVSS 141 procedure for light-duty passenger vehicles. Analysis of the measured data found the FMVSS 141 forward gear criteria to be reasonably effective when applied to the test vehicle, but the standard’s reverse gear criteria were deficient to other common industry-accepted backing alert methods. These results are used as a starting point for a discussion on various aspects of FMVSS 141, with an emphasis on how adding commercial vehicles to the scope of the standard could necessitate further changes to the defined acceptance criteria.