Exhibit 99.2


                                  CERTIFICATION
                       PURSUANT TO 18 U.S.C. SECTION 1350,
                       AS ADOPTED PURSUANT TO SECTION 906
                        OF THE SARBANES-OXLEY ACT OF 2002

     In connection with the Knight Transportation,  Inc., an Arizona corporation
(the "Company")  Quarterly  Report on Form 10-Q for the three month period ended
June 30, 2002, as filed with the Securities and Exchange  Commission on the date
hereof,  I, Timothy M. Kohl,  Chief Financial  Officer of the Company,  certify,
pursuant to 18 U.S.C.  Section 1350,  as adopted  pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002, that:

     To the best of the  undersigned's  knowledge,  based  upon a review  of the
Company's Form 10-Q for the three month period ended June 30, 2002:

     1.   The Company's Quarterly Report on Form 10-Q for the three month period
          ended June 30, 2002,  fully complies with the  requirements of Section
          13(a) or 15(d) of the Securities Exchange Act of 1934;

     2.   The  information  contained in the  Company's  Form 10-Q for the three
          month  period ended June 30, 2002,  fairly  presents,  in all material
          respects,  the  financial  condition  and results of operations of the
          Company.


                                        /s/ Timothy M. Kohl
                                        ----------------------------------------
                                        Timothy M. Kohl
                                        Chief Financial Officer
                                        Principal Financial Officer


STATE OF ARIZONA    )
                    )
County of Maricopa  )

     The foregoing was acknowledged  before me this 9th day of August,  2002, by
Timothy M. Kohl,  Chief  Financial  Officer of Knight  Transportation,  Inc., an
Arizona corporation, on behalf of such corporation.



                                        /s/ Eric Franco Frausto
                                        ----------------------------------------
                                        Notary Public
My Commission Expires:

January 01, 2005
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     This  certification  is made solely for purpose of 18 U.S.C.  Section 1350,
subject  to the  knowledge  standard  contained  therein,  and not for any other
purpose.