It follows concerns expressed by the National Highway Traffic Safety Administration (NHTSA), which claims the silent running of electric and hybrid vehicles threatens the safety of visually impaired pedestrians.

The action is mandated by the Pedestrian Safety Enhancement Act of 2010, which will help NHTSA lay out the groundwork for proposed rules that will help pedestrians to detect quieter vehicles. NHTSA will be responsible for evaluating the merits of the rules, including requirements for manufacturers to add sounds to electric vehicles.

NHTSA 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 American public has 30 days to submit comments on the NHTSA action.