SECOND AMENDMENT
                                       TO
                        NET LEASE AND JOINT USE AGREEMENT



                  This  Second  Amendment  to Net Lease and Joint Use  Agreement
("Lease") is made and entered into this day by and between L. Randy  Knight,  as
Trustee  of the  R.K.  Trust,  dated  April 1,  1993  ("Landlord"),  and  Knight
Transportation, Inc., and Arizona corporation ("Tenant").

                                    Recitals
                                    --------

                  A. As of March 1, 1994,  Tenant  entered  into a Lease with L.
Randy  Knight,  a  married  man  dealing  with his sole  and  separate  property
("Knight").  By  Assignment  and  First  Amendment  to Net  Lease  and Joint Use
Agreement dated September 1, 1994,  Knight assigned all of his right,  title and
interest in the Lease to Landlord.

                  B.  Landlord  and Tenant have agreed to increase the amount of
space being leased from  Landlord to Tenant and desire to modify  certain  other
terms and conditions of the Lease.

                  Accordingly,  effective as of September 1, 1997,  the Lease is
amended as follows:

                                    Amendment
                                    ---------

                  1. The last sentence of Section 2.2, Premises of the Lease, is
deleted and the following substituted therefor:

                           2.2 Said leasehold space,  including all land
                  and improvements, is herein called the "Premises." The
                  Premises,  as of September 1, 1997, consists of 31,356
                  square feet of  improved  space  ("Office  Space") and
                  393,139  square  feet  of  parking,   maintenance  and
                  terminal space  (hereinafter,  the "Terminal  Space").
                  The Office Space and the Terminal Space  constitute in
                  total approximately 9.7450 acres.

                  2.  Section  3.3 of the  Lease is  deleted  and the  following
provision substituted therefor:

                                 Exhibit 10.2.2

                           3.3  Expansion  of Office  Space.  During the
                  term of this Lease and any Option  Term,  Tenant shall
                  have  the  right  to  expand  the   Office   Space  in
                  increments  of not less  than  2,240  square  feet (as
                  determined  by  the  Building   Structural   Post)  by
                  notifying  the  Landlord  in writing  (the  "Expansion
                  Notice")  60 days  prior to  exercising  its option to
                  expand   Tenant's   Office  Space.   Upon  giving  the
                  Expansion  Notice,  Tenant  shall be  obligated to pay
                  additional Base Rent for the additional  Office Space,
                  which will be an amount  equal to the number of square
                  feet by which  the  Tenant's  Office  Space  expanded,
                  multiplied by $1.236.

                  3. The  introductory  paragraph and  paragraphs (a) and (b) of
Section  4,  Rent  of the  Lease,  are  deleted  and  the  following  provisions
substituted therefor:

                           4. Commencing  September 1, 1997, the monthly
                  Base Rent shall be  $5,922.72  per month.  The monthly
                  Base  Rent is based  upon a rental of  $.00515  square
                  feet per  month  for the  Terminal  Space  and  $.1236
                  square feet for Office  Space.  The total  square feet
                  leased by Tenant is  described  in  Exhibit B attached
                  hereto.  The Base Rent shall be adjusted as  described
                  in Sections 3.3 and 4.2, below.

                                             (a) During the Initial Term
                  of this Lease and any Option  Terms,  Tenant shall pay
                  to Landlord Base rent for the Premises,  without prior
                  notice or demand.  Tenant  shall pay Landlord the Base
                  Rent for the first month's occupancy,  in advance,  on
                  the Commencement Date.

                                             (b)  Rent  for  any  period
                  during the initial term or any option term that is for
                  less than one month  shall be prorated on the basis of
                  a 30 day month.

                  4. Exhibit B to the Lease is hereby deleted, and Exhibit B, as
attached hereto is substituted therefor.
                                       -2-

                  5. All other terms and conditions of the Lease shall remain as
constituted  immediately  prior to the effective date of this Second  Amendment.
Landlord and Tenant ratify,  confirm and approve the Lease as amended hereby and
each agrees that the Lease is in full force and effect.

                  Dated as of this 1st day of September, 1997.

                                        TENANT:

                                        KNIGHT TRANSPORTATION, INC.


                                        By    /s/   Kevin P. Knight
                                           -------------------------------------
                                           Kevin P. Knight
                                           Chief Executive Officer



                                        LANDLORD:

                                        R.K. TRUST dated April 1, 1993



                                        By      /s/    L. Randy Knight
                                           -------------------------------------
                                           L. Randy Knight, Trustee
                                      -3-