Shareholders of truckload carrier Knight Transportation Inc. late yesterday approved its $6 billion merger with rival truckload carrier Swift Transportation LLC, the largest trucking deal in history.

Following the move, the merger closed today.

On April 9, (NYSE: KNX) ("Knight") today announced that its stockholders approved its merger with Swift Transportation Company (NYSE: SWFT) ("Swift") at a special meeting of Knight stockholders held earlier today. Knight stockholders approved all proposals put forward at the special meeting.

The all-stock deal, announced April 9, creates a $5.1 billion transportation and logistics giant with footprints in dry van and refrigerated transport, dedicated contract carriage, cross-border Mexico and Canada operations, truck brokerage, and intermodal. The fleet will consist of approximately 23,000 tractors and 77,000 trailers. It is the nation's largest truckload carrier. Swift, with about 18,000 tractors, had been the nation's largest trucking company based on fleet size.

The combined company has been named Knight-Swift Transportation Holdings Inc.