When noise is a problem, it’s usually in the “too much” rather than “too little” category. The opposite is true of ultra-quiet electric and hybrid vehicles, who emit so little noise that pedestrians and bicyclists may not be able to detect their presence, thus increasing their chances of an accident.

The National Fire Protection Association (NFPA) is hailing a decision by Massachusetts to offer drivers of electric and hybrid vehicles special license plates, to easily identify them to first responders.