The electric motors of many electric and hybrid vehicles run quietly, and can present a danger to any pedestrians who can’t hear a vehicle coming. For that reason, these vehicles will be required to emit alerts when traveling under 18.6 mph by 2019. The new rule will help prevent approximately 2,400 injuries every year.

According to the U.S. Department of Transportation, vehicles that travel above 18.6 mph generate sufficiently loud tire and wind noises to alert pedestrians to their presence. And, as electric and hybrid vehicles continue to gain popularity with consumers, the agency believes that the rule will help keep more pedestrians and drivers safe.

The rule is expected to cost auto manufacturers approximately $39 million annually. However, the National Highway Traffic Safety Administration (NHTSA) has stated that the benefits of reduced injuries to pedestrians and drivers will be about $250 million to $320 million annually.