Transportation Secretary Ray LaHood announced Sunday that the Federal Aviation Administration and the Air Traffic Controllers Union have reached an agreement to make changes in the aftermath of recent incidents involving sleeping air traffic controllers. The changes will be effective immediately.

Controllers will now have a minimum of nine hours off between shifts. Currently they were getting as few as eight. Controllers will no longer be able to swap shifts unless they have a minimum of nine hours off between the last shift they worked and the one they want to begin. They will no longer be able to switch to an unscheduled midnight shift following a day off.

FAA managers will schedule their own shifts in a way to ensure greater coverage in the early morning and late night hours.

On Saturday, the FAA suspended another traffic controller caught sleeping. The incident occurred at the Miami Air Route Traffic Control Center during the midnight shift early Saturday morning, the agency reported.