Item 5.04 Temporary Suspension of Trading Under Registrant's Employee Benefit Plans

On October 22, 2012, Knight Transportation, Inc. (the "Company") received a notice from the Plan Administrator for the Knight Transportation, Inc. 401(k) Plan (the "Plan") of a blackout period (the "Blackout Period") with respect to the Plan pursuant to Section 101(i)(2)(E) of the Employee Retirement Income Security Act of 1974, as amended. The Blackout Period is required because the Plan is changing its administration from Prudential Financial, Inc. to Diversified Retirement Corporation. During the Blackout Period, participants in the Plan will be unable to change their contribution rates, request withdrawals or distributions, request new loans, change investment selections or otherwise perform account transactions under the Plan, including the Common Stock of the Company, which is an investment option under the Plan. The Blackout Period begins on November 26, 2012 and is expected to end during the week of December 16, 2012. Interested parties may obtain, without charge, information regarding the Blackout Period by contacting Vicki Williams, Benefits Administrator, Knight Transportation, Inc., 5601 West Buckeye Road, Phoenix, Arizona 85043, (602) 606-6297.

Under Regulation BTR, transactions by Company directors and officers in Company securities will be restricted during the Blackout Period. A notice to this effect was provided to the Company's directors and officers.

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