WASHINGTON — The U.S. government said on Monday it will require new cars and light trucks sold in the United States to have rear view cameras by May 2018, a regulation intended to prevent drivers from backing into pedestrians.

The National Highway Traffic Safety Administration said the new requirement will apply to all vehicles under 10,000 pounds, including buses and trucks.

“Rear visibility requirements will save lives, and will save many families from the heartache suffered after these tragic incidents occur,” said NHTSA Acting Administrator David Friedman said in a statement.

NHTSA said that 58 to 69 lives will be saved each year once all cars and light trucks on the road have this technology.

There are, on average, 210 fatalities and 15,000 injuries per year caused by backover accidents, the agency said. Children under 5 years old and adults 70 and older account for more than half of all backover fatalities each year.

Many automakers already are installing rear view cameras in response to consumer demand.

Safety watchdogs welcomed the new rule but faulted the Obama administration for not moving sooner. In 2008, Congress directed the Transportation Department, which oversees NHTSA, to issue a rear visibility standard by 2011 but it was repeatedly delayed.

“While the administration delayed the rule, more children died in backover accidents. The cost of regulatory delay, in human lives, could hardly be more clear than it is today,” Robert Weissman, president of Public Citizen, said in a statement.

Cameras must be able to give drivers a 10-foot-by-20-foot field of view directly behind the vehicle, NHTSA said. The video system also must meet other requirements, including image size.

The agency estimated that it would cost between $132 and $142 to equip each vehicle with a rearview camera that meets the requirements.