The National Highway Traffic Safety Administration (NHTSA) has adopted a law, according to which from September 2019 all electric and hybrid vehicles that are on sale in the USA, will be required to make warning signals under speed conditions 19 mph or less. In particular, the electric car or hybrid should make one or multi-tone audible sound on a frequency of from 315 to 5000 Hz. The law has been adopted in view of the fact that, unlike cars with internal combustion engines, electric vehicles travel almost silently at low speeds thereby creating a rather dangerous situation for pedestrians. Because of this, a pedestrian-road accident can happen because people may not just hear the car approaching. The warning sound system should work not only during the forward running but also when the car is in reverse. It bears reminding that three years ago, the head of Tesla Motors Elon Musk, answering questions about the safety of pedestrians, informed that many owners of Tesla were worried about children who could spring out on the road without noticing an approaching car.
According to estimates of the NHTSA, 50% of the cars must meet the conditions by September 2018. At the same time the NHTSA in its report does not specify what kind of sound has to be made by the slowly driving electric and hybrid cars. Electric cars will be equipped with special "equipment" from 2019. In Musk's opinion, the installation of special indicators that will be able to sense the position of a pedestrian would be the best solution in this case. And Toyota since 2012 has equipped all its Prius hybrids (delievered to the Japanese market) with a special sound system.