The acoustic performance of seven vehicles was evaluated according to Canadian
Motor Vehicle Safety Standard 141 (CMVSS 141), which governs minimum required
sound levels for hybrid and electric vehicles with a gross vehicle weight rating
(GVWR) of 4536 kg (10,000 lb) or less. To better understand the sound profiles
of medium-duty electric vehicles (MDEVs) and heavy-duty electric vehicles
(HDEVs), the sound emissions of two light-duty electric vehicles (LDEVs), one
MDEV, three HDEVs, including an electric transit bus, and one heavy-duty
internal combustion engine (HD ICE) vehicle were compared. The sound emissions
of the MDEV and HDEVs were quieter than the HD ICE vehicle and comparable to
that of the LDEVs equipped with auxiliary speakers. The MDEV with its auxiliary
speaker turned off and all three HDEVs without auxiliary speakers met CMVSS 141
requirements in reverse gear and at speeds of 20 km/h and 30 km/h. The MDEV,
though not subject to CMVSS 141, failed to meet the minimum sound requirement at
stationary when its auxiliary speaker was deactivated. Similarly, the electric
transit bus did not meet sound requirements at stationary and 10 km/h,
highlighting the potential of acoustic vehicle alert systems (AVAS) in enhancing
the detectability of quiet vehicles.