Federal regulators say they will require that new tour buses and buses that carry passengers on scheduled routes between cities be equipped with seat belts. It’s a safety measure sought by accident investigators for nearly a half century.

The National Highway Traffic Safety Administration said Wednesday that beginning in November 2016 all new motorcoaches and other large buses must be equipped by manufacturers with three-point lap-shoulder belts.

The agency said an average of 21 people in such buses are killed each year in crashes, and thousands more are injured annually. The agency said seat belts could reduce fatalities and moderate-to-severe injuries by nearly half.

Federal accident investigators first recommended motorcoaches be equipped with seat belts in 1968 in response to a California highway crash that killed 19 passengers.

(AP)