SECOND MODIFICATION AGREEMENT

         BY THIS SECOND  MODIFICATION  AGREEMENT (the "Agreement"),  dated as of
the 3rd day of August, 1998, WELLS FARGO BANK, N.A., as administrative agent for
the Banks listed in the hereinafter  defined Credit  Agreement (the "Banks") and
as Issuing Bank, and SWIFT TRANSPORTATION CO., INC., an Arizona corporation (the
"Borrower"), in consideration of the mutual covenants herein contained and other
good and valuable consideration,  the receipt and sufficiency of which is hereby
acknowledged, hereby confirm and agree as follows:

SECTION 1. RECITALS.

         1.1  Borrower  and the  Administrative  Agent,  ABN AMRO Bank  N.V.  as
Co-Agent,  and the Banks  entered into that Credit  Agreement  dated January 16,
1997  (the  "Credit  Agreement")  to  provide  financial  accommodations  to the
Borrower as provided therein,  which Credit Agreement was previously  amended by
that Modification Agreement dated September 25, 1997.

         1.2  Borrower  and the  Administrative  Agent,  with the consent of the
Banks, desire to modify the Agreement as set forth herein.

         1.3 All undefined  capitalized terms used herein shall have the meaning
given them in the Credit Agreement.

         1.4 The "Effective Date" means August 6, 1998,

SECTION 2. CREDIT AGREEMENT

         2.1 The  following  definitions  contained in Section 1.1 of the Credit
Agreement are hereby amended to read as follows:

                  "Maturity Date" shall mean January 16, 2003.

                  "Maximum Commitment" shall mean $170,000,000.00.

         2.2 Schedule 2.1 to the Credit  Agreement is hereby  amended to read as
attached hereto.

         2.3 Article V of the Credit Agreement is hereby amended by the addition
of the following Section 5.9:

                  Section 5.9 YEAR 2000  COMPLIANT.  Perform all acts reasonably
         necessary to ensure that  Borrower  and any business in which  Borrower
         holds a  substantial  interest  become Year 2000  Compliant in a timely
         manner.  Such acts shall  include,  without  limitation,  performing  a
         comprehensive  review and  assessment of all of  Borrower's systems and


         adopting  a plan for the  remediation,  monitoring and  testing of such
         systems. As used in this  paragraph, "Year 2000  Compliant" shall mean,
         in regard to  any  entity,  that  all  software,  hardware,  firmware,
         equipment,  goods or systems  material to the  business  operations  or
         financial   condition  of  such  entity,  will  properly  perform  date
         sensitive   functions   after  December  31,  1999.   Borrower   shall,
         immediately  upon  request,  provide to the  Administrative  Agent such
         certifications  or other  evidence of  Borrower's  compliance  with the
         terms of this paragraph as the Banks may from time to time require.

SECTION 3. OTHER MODIFICATIONS, RATIFICATIONS AND AGREEMENTS.

         3.1 All references to the Credit  Agreement in the other Loan Documents
are hereby amended to refer to the Credit Agreement as hereby amended.

         3.2 Borrower hereby reaffirms to the Banks each of the representations,
warranties,  covenants  and  agreements  of  Borrower  set  forth in the  Credit
Agreement,  with the same  force and  effect as if each were  separately  stated
herein  and  made  as  of  the  date   hereof  and  hereby   affirms   that  the
representations  and warranties set forth in Article III of the Credit Agreement
remain  true and correct in all  material  respects  as of the  Effective  Date,
except to the extent such  representations  and warranties  expressly relate and
are limited to a different date.

         3.3 Borrower hereby represents and warrants to the Administrative Agent
and the Banks that it has reviewed the areas within its business and  operations
and that of its  Subsidiaries  which  could be  adversely  affected  by, and has
developed  or is  developing a program to address on a timely  basis,  the "Year
2000 Problem" (that is, the risk that computer applications used by the Borrower
and  its   Subsidiaries   may  be  unable  to  recognize  and  perform  properly
date-sensitive  functions  involving  certain  dates prior to and any date after
December  31,  1999),  and has made  related  appropriate  inquiry  of  material
suppliers and vendors.  Based on such review and program,  the Borrower believes
that the "Year 2000 Problem" will not result in a Material  Adverse  Change with
respect to the Borrower.

         3.4 Borrower hereby ratifies, reaffirms,  acknowledges, and agrees that
the Notes and the Credit Agreement represent valid,  enforceable and collectible
obligations  of  Borrower,  and that  there are no  existing  claims,  defenses,
personal or  otherwise,  or rights of setoff  whatsoever  with respect to any of
these documents or instruments.  Borrower  further  acknowledges  and represents
that no event has occurred and no condition  exists that,  after notice or lapse
of time, or both, would constitute a default under this Agreement,  the Notes or
the Credit Agreement.

         3.5 All terms,  conditions and  provisions of the Credit  Agreement are
continued in full force and effect and shall  remain  unaffected  and  unchanged
except as specifically amended hereby. The Credit Agreement,  as amended hereby,
is hereby  ratified  and  reaffirmed  by  Borrower,  and  Borrower  specifically
acknowledges the validity and  enforceability  thereof.  The Credit Agreement is
hereby  modified  to  provide  that it shall be a default or an event of default
thereunder  if  Borrower  shall  fail to  comply  with any of the  covenants  of

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Borrower  herein or if any  representation  or warranty by Borrower herein or by
any  guarantor  in  the  Consent  and  Agreement  of  Guarantors  is  materially
incomplete, incorrect, or misleading as of the date hereof.

         3.6 Any Bank whose  Commitment is changed to zero on the Effective Date
shall  deliver  one  or  more  executed   Assignments  and  Acceptances  to  the
Administrative  Agent and shall upon the Effective Date cease to be a Bank party
to the Credit Agreement.

         3. 7 Each  Person  listed on the  revised  Schedule  2.1 which is not a
party to the Credit  Agreement shall, if required by the  Administrative  Agent,
deliver to the  Administrative  Agent an executed  Administrative  Details Reply
Form and shall become a Bank party to the Credit  Agreement  upon the  Effective
Date.

SECTION 4. GENERAL.

         4.1 This  Agreement  in no way acts as a release or  relinquishment  of
those rights  securing  payment of the Loans.  Such rights are hereby  ratified,
confirmed, renewed and extended by Borrower in all respects.

         4.2 The  modifications  contained  herein shall not be binding upon the
Banks until the later of the Effective Date or the date when the  Administrative
Agent shall have  received  from each Bank an executed  Consent of the Banks and
from the Borrower all of the following:

                  (a) An  original  of  this  Agreement  fully  executed  by the
         Borrower.

                  (b) An original of the Consent  and  Agreement  of  Guarantors
         fully executed by the Guarantor and Swift Leasing.

                  (c) A duly executed Note for each Bank,  dated as of August 3,
         1998, in the amount shown on Schedule 2.1 hereto.

                  (d)  An  amended  and  restated  Continuing   Guarantee  fully
         executed by the Guarantor and Swift Leasing.

                  (e)  Such  resolutions  or   authorizations   and  such  other
         documents  as the  Administrative  Agent may  require  relating  to the
         existence  and good  standing of the  Borrower  and  Guarantor  and the
         authority of any person  executing this Agreement or other documents on
         behalf of the Borrower and Guarantor.

         4.3 Borrower shall execute and deliver such additional documents and do
such  other acts as the Banks may  reasonably  require  to fully  implement  the
intent of this Agreement.

         4.4  Borrower  shall  pay all costs and  expenses,  including,  but not
limited to, reasonable  attorney's fees incurred by the Administrative  Agent in
connection herewith, whether or not all of the conditions described in Paragraph
4.2 above  are  satisfied.  Banks, at their  option, but  without any obligation

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to do so,  may  advance  funds to pay any such costs and  expenses  that are the
obligation of the Borrower,  and all such funds  advanced shall bear interest at
the highest rate provided in the Notes and shall be due and payable upon demand.

         4.5 Notwithstanding anything to the contrary contained herein or in any
other instrument executed by Borrower, the Administrative Agent or the Banks, or
in any other action or conduct undertaken by Borrower,  the Administrative Agent
or the  Banks on or  before  the date  hereof,  the  agreements,  covenants  and
provisions  contained  herein shall  constitute  the only evidence of the Banks'
consent to modify the terms and provisions of the Credit Agreement. Accordingly,
no express or implied consent to any further modifications  involving any of the
matters set forth in this Agreement or otherwise shall be inferred or implied by
the  Banks'  consent to this  Agreement.  Further,  the  Banks'  consent to this
Agreement  shall not  constitute  a waiver  (either  express or  implied) of the
requirement that any further  modification of the Credit Agreement shall require
the express  written  consent of the Banks;  no such consent  (either express or
implied) has been given as of the date hereof.

         4.6 Time is hereby  declared to be of the essence  hereof of the Credit
Agreement, and Banks require, and Borrower agrees to, strict performance of each
and every covenant,  condition,  provision and agreement  hereof,  of the Credit
Agreement.

         4.7 This  Agreement  shall be  binding  upon,  and  shall  inure to the
benefit  of, the  parties  hereto  and their  heirs,  personal  representatives,
successors and assigns.

         4.8 This  Agreement is made for the sole  protection and benefit of the
parties  hereto,  and no other  person or entity  shall have any right of action
hereon.

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         4.9 This Agreement shall be governed by and construed  according to the
laws of the State of Arizona.

         IN  WITNESS  WHEREOF,  these  presents  are  executed  as of  the  date
indicated above.

                                             WELLS FARGO BANK, N.A.


                                             By: /s/ Stephanie Arnold
                                                --------------------------------
                                             Name: Stephanie Arnold
                                                  ------------------------------
                                             Its: Vice President
                                                 -------------------------------

                                                            ADMINISTRATIVE AGENT
                                                                AND ISSUING BANK



                                             SWIFT TRANSPORTATION, CO., INC., an
                                             Arizona corporation


                                             By: /s/ William F. Riley III
                                                --------------------------------
                                             Name: William F. Riley III
                                                  ------------------------------
                                             Its:  EVP - CFO
                                                 -------------------------------

                                                                        BORROWER
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