According to the National Highway Traffic Safety Administration (NHTSA), adding noise to EVs for speeds 0-30km/h would prevent about 2,800 injuries over the life of each model year of vehicles.
Speakers & costs
According to NHTSA, adding the needed speaker system would increase the cost of manufacturing a car or light truck by about $30 (€22,86), or $23,5 million (€17,91 million) for the whole industry in 2016.
Beyond the cost of those components, the added weight would increase fuel costs by about $5 (€3,81) over the lifetime of a light vehicle, NHTSA says. That, combined with the $30 (€22,86) in components, means the total cost of a vehicle would increase by about $35 (€26,67).
Requirement or Recommendation?
To meet the requirements, automakers would need to add speakers that are audible from the street, but still protected from the elements. Nissan, Toyota, Chevrolet, Ford already did that with their EVs, but with the possibility of removing this feature, except for Toyota as advocates for the blind and the elderly have insisted is necessary.
Under the current proposal, drivers would not be able to deactivate the warning sound while a vehicle is in motion, which NHTSA says "would compromise pedestrian safety."
However, it is not clear yet in the proposal whether vehicles would be required to make noise while idle.
The Pedestrian Safety Enhancement Act (PSEA)
The establishment of “Minimum Sound Requirements for Hybrid and Electric Vehicles” is a requirement under the PSEA of 2010. To meet this standard would require hybrid and electric passenger cars, LTVs, medium and heavy duty trucks and buses, LSVs, and motorcycles to produce sounds.
The PSEA requires NHTSA to establish performance requirements for an alert sound that is recognisable as motor vehicle in operation that allows blind and other pedestrians to reasonably detect a nearby BEV or HEV operating below the crossover speed (at which tire noise, wind noise, and other factors eliminate the need for a separate alert sound).
This proposed standard applies to BEVs and to any HEV capable of propulsion in any forward or reverse gear without the vehicle’s ICE operating.