January 8, 2013
Federal Agency Says Electric Cars Are Too Quiet, Wants Law To Make Them Louder
Brett Smith for redOrbit.com - Your Universe Online
Of all the benefits conveyed by the emergence of electric cars, the one thing that often goes unmentioned is that they are quiet — maybe a little too quiet.
Most of us would agree that the approaching sound of a car engine is so familiar and so ingrained in our minds through experience that we perk up at the sound and instinctively scan the immediate area for a vehicle that might be headed our way.
The rumbling of a combustion engine often serves as a de facto warning for pedestrians and bicyclists who share parts of the road with cars and trucks, and in their absence they may be less aware of approaching traffic. In recognition of this ℠problem,´ the National Highway Traffic Safety Administration (NHTSA) has proposed that electric autos be legally required to come equipped with a device that creates a synthetic sound to serve the same purpose.
“This standard will ensure that blind, visually-impaired, and other pedestrians are able to detect and recognize nearby hybrid and electric vehicles by requiring that hybrid and electric vehicles emit sound that pedestrians will be able to hear in a range of ambient environments and contain acoustic signal content that pedestrians will recognize as being emitted from a vehicle,” said an official statement put out by the agency on Monday.
The proposed rule would require cars powered by electric motors to make additional noise when traveling under 18 miles per hour. NHTSA said that the wind noise generated by these cars allows them to be heard at higher speeds.
The administration also provided carmakers with an array of potential sounds in the form of audio files on its website. A cursory examination of the noises revealed them to be a series of engine idling sounds with slight tweaks to each one, including a few that contained a futuristic whirring tone. The sounds were designed to create a change in pitch as the speed of the car increases. According to the NHTSA, there should be a “one percent shift in pitch frequency of the vehicle sound per km/h of acceleration to ensure that pedestrians would be able to determine whether an [electric vehicle] is accelerating or decelerating.”
To make the digital files audible, the proposed regulations will require carmakers to install “a dynamic range speaker system that is protected from the elements and attached with mounting hardware and wiring to both power the speaker and receive signal inputs and a digital signal processor that receives information from the vehicle regarding vehicle operating status (to produce sounds dependent upon vehicle status).”
Estimates from the NHTSA peg the average cost of these systems at around $30 that would likely be passed on to the consumer, yet the agency said the additional costs would translate into the prevention of 2,800 pedestrian and cyclist injuries during the life of each model year of electric and hybrid autos. It remains unclear, however, how the agency arrived at these numbers.
The agency noted that the public has 60 days to comment on the proposed rules. They said all feedback will be considered when crafting a proposal.
A new noisemaking system could have a widespread impact on the growing hybrid and electric car industry, which is estimated to reach 3.8 million vehicles by 2020, according to new research from the technology consultant agency Pike Research.