WASHINGTON — The Transportation Department issued a rule Monday that will require rearview cameras in many new vehicles in an effort to reduce deaths and serious injuries caused by backup accidents.

The final rule issued by the National Highway Traffic Safety Administration will require new vehicles under 10,000 pounds and built on-or-after May 1, 2018 to meet the new rear-visibility standards. The rule includes buses and trucks. Motorcycles and trailers are exempt.

The rearview cameras must give drivers a field of vision measuring at least 10 by 20 feet directly behind the vehicle. The system must also meet other requirements including dashboard image size, lighting conditions and display time.

Backup accidents involving light vehicles cause an average of 210 deaths and 15,000 injuries a year, and victims often include children and the elderly, the government said.

The agency said the new rule, required in the Cameron Gulbransen Kids Transportation Safety Act, will save 13 to 15 lives per year and prevent as many as 1,125 injuries per year. The measure, signed into law in 2008, was named for a 2-year-old Long Island boy whose pediatrician father backed over him in their driveway in 2002.

The government estimates that a rearview system will cost $132 to $142 per vehicle. It will cost about $43 to $45 for vehicles that already have a dashboard display screen, but need upgrades to comply with the rule.

Compliance will be phased in by manufacturers starting in May 2016, before it becomes mandatory two years later.