WASHINGTON (Reuters) - The U.S. government on Monday finalized long-delayed rules that will require “quiet cars” like electric vehicles and hybrids to emit alert sounds when they are moving at speeds of up to 18.6 miles per hour (30 km per hour) to help prevent injuries among pedestrians, cyclists and the blind.

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The rules, which were required by Congress, will require automakers like Tesla Motors Inc TSLA.O, Nissan Motor Co 7201.T and Toyota Motor Corp 7203.T to add the sounds to all vehicles by September 2019. The U.S. Transportation Department said it expects the rules would prevent 2,400 injuries a year by 2020 and require the addition of alert sounds to about 530,000 2020 model vehicles.

The U.S. National Highway Transportation Department said the rules will cost the auto industry about $39 million annually because automakers will need to add an external waterproof speaker to comply. But the benefits of the reduced injuries are estimated at $250 million to $320 million annually.

NHTSA estimates the odds of a hybrid vehicle being involved in a pedestrian crash are 19 percent higher compared with a traditional gas-powered vehicle. About 125,000 pedestrians and bicyclists are injured annually.

The rules will also help the blind and visually impaired.

“This is a common-sense tool to help pedestrians, especially folks who are blind or have low vision, make their way safely,” said NHTSA Administrator Dr. Mark Rosekind in a statement.

The rules apply to hybrid and electric cars, SUVs, trucks and buses weighing up to 10,000 pounds and seek to prevent crashes at intersections or when electric vehicles are backing up.

NHTSA originally proposed extending the sound requirements to all vehicles, including motorcycles and larger trucks and buses.

At higher speeds, the alert is not required because other factors like tire and wind noise adequately warn pedestrians, NHTSA said.

Advocates for blind people have pushed for the rules and praised the announcement.

Automakers had raised concerns about the alerts, saying they are too loud and complicated. The rules set minimum sound requirements but do not specify what sounds must be emitted.

The Alliance of Automobile Manufacturers, a trade group, said in a statement “it’s important that automakers have the flexibility to equip vehicles with sounds that are sufficiently detectable yet pleasant to hear; consumer acceptance is critical and that hinges on sounds not annoying people inside the auto.”

Under a 2010 law passed by Congress, NHTSA was supposed to finalize the regulations by January 2014, but the rules were subjected to a lengthy White House review.

The Trump administration could opt to review the rules once it takes office.