There’s a koan in Zen Buddhism that effectively asks, “What is the sound of one hand clapping?” The National Highway Traffic Safety Administration won’t address that question, but they’ll soon address another: what is the correct pedestrian alert noise for an electric or hybrid vehicle?
The agency is set to propose a rule requiring both hybrid and electric vehicles to emit a pedestrian warning tone when vehicle speeds drop below 20 kilometers per hour (12.4 miles per hour). Per the agency’s directive, the sound must be automatically generated (unlike the Chevy Volt, which requires driver intervention to sound a warning tone) and cannot sound like sirens, chimes, bells, horns or music. Also excluded from consideration is ambient background noise, like waves, animals, insects or running water.
The agency specifies that the sound must be variable with speed and cannot be louder than engine noise from an internal combustion engine vehicle operated at 20 kilometers per hour. The agency doesn’t define what that noise level is, and a Lamborghini Gallardo at 20 kilometers per hour is quite a bit louder than a Toyota Yaris at the same speed. Oddly enough, the NHTSA mandate doesn’t include internal combustion engine cars that fall below the noise level of an average vehicle at 20 kph.
The NHTSA maintains that hybrid vehicles have a higher instance of pedestrian accidents than traditional gasoline-powered vehicles, even though other studies seem to conflict with this conclusion. In a statement released by the agency, administrator David Strickland said, “Even as we make giant leaps forward with hybrid and electric vehicles, we must remain laser focused on safety. With more and more quiet vehicles on the road, we have to consider their effect on pedestrians.”
The NHTSA has until July 4, 2012 to draft a proposal for the pedestrian alert tone, and a final ruling is due by January 4, 2014. Once set, manufacturers will have until September of 2017 to include the warning tone on hybrid and electric vehicles.