WASHINGTON (AP) — The Federal Aviation Administration said Wednesday it will increase minimum rest time between shifts for air traffic controllers after highly publicized close calls between planes that were following orders from controllers.

The FAA and the National Air Traffic Controllers Association, the union representing the workers, agreed to a number of changes that will apply as schedules are negotiated for next year.

“The science is clear that controller fatigue is a public safety issue, and it must be addressed,” FAA Administrator Mike Whitaker said. He promised more measures to address tired controllers.

Rich Santa, president of the controllers’ union, said the group has been raising concern about fatigue for years. He said the agreement “will begin to  provide relief to this understaffed workforce.”

A report by experts to the FAA recommended 10 to 12 hours of rest before all shifts as one way to reduce the risk that tired controllers might make mistakes. The panel also said additional time off might be needed before midnight shifts, which don’t allow workers to follow normal sleep patterns.

The agreement between the FAA and the union will give controllers 10 hours off between shifts and 12 hours off before and after a midnight shift. They also agreed to limit consecutive overtime assignments.

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The FAA has limited the number of flights in New York and Florida because of a shortage of air traffic controllers. Whitaker said the FAA will hire 1,800 controllers this year and is expanding its ability to hire and train controllers.

Controllers have been in the center of some close calls. The National Transportation Safety Board said in January that a controller made faulty assumptions that led him to clear a FedEx plane to land in Austin, Texas, while a Southwest Airlines jet was taking off from the same runway. Fatigue was not cited as a factor.

In other cases, controllers have stepped in to stop runway conflicts that could have been disastrous, including when an American Airlines jet mistakenly crossed an active runway at JFK Airport in New York.