

Way back at the dawn of the automobile, people were skeptical of the new invention. They were accustomed to horses, and the UK passed a law that required motorists to be preceded by a man on foot waving a red flag so as to warn pedestrians.

Well, a 21st-century equivalent of that practice is on the way. A new rule announced by the US National Highway Traffic Safety Administration on Monday will require electric vehicles (plug-in hybrid EVs as well as battery EVs) to make some noise at low speed to warn oncomers.

At speeds of 19mph (30km/h) or below—either moving forward or in reverse—EVs will need an audible warning. Above that speed, a warning is not considered necessary because tire and wind noise should provide sufficient notice to the visually impaired that a vehicle is headed their way.

"We all depend on our senses to alert us to possible danger," said US Transportation Secretary Anthony Foxx. "With more, quieter hybrid and electrical cars on the road, the ability for all pedestrians to hear as well as see the cars becomes an important factor of reducing the risk of possible crashes and improving safety."

While this might at first glance seem like a silly idea, the organizers of the annual Pikes Peak International Hill Climb in Colorado have insisted on for years. EVs have become more popular at Pikes Peak of late because, unlike their internal combustion rivals, they are unaffected by the climb in altitude. Organizers have required EVs competing in the race to use sirens to alert the corner workers that a vehicle is approaching.

Automakers have until September 1, 2019 to comply with the new safety standard.

Listing image by Elle Cayabyab Gitlin