DALLAS -- Federal safety investigators say a Texas driver suffering from "acute sleep deficit" failed to maintain his lane and caused his passenger bus to careen out of control, resulting in a wreck that killed nine people and injured nearly 40 others in 2016.

• Bus was traveling from Brownsville to Eagle Pass
• Driver survived the wreck
• Bus had an inoperable antilock braking system

The National Transportation Safety Board released its final report on the crash Tuesday. The agency determined the bus left the road and rolled when the 29-year-old driver overcorrected and abruptly braked. Inspectors say the road was wet from a recent rain and that the bus had an inoperable antilock braking system.

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The bus began its trip in Brownsville, in far South Texas, and was en route to the Kickapoo Lucky Eagle Casino in Eagle Pass in May 2016.

Seven passengers died at the scene. Two others died later. The driver survived the wreck.