Exhibit 5


                       [SNELL & WILMER L.L.P. LETTERHEAD]


                                August 22, 2002


Swift Transportation Co., Inc.
2200 South 75th Avenue
Phoenix, Arizona 85043

     Re: SWIFT TRANSPORTATION CO., INC. 1999 STOCK OPTION PLAN

Ladies & Gentlemen:

     We have acted as counsel to Swift Transportation Co., Inc., a Nevada
corporation (the "Company"), in connection with the preparation of its
Registration Statement on Form S-8 (the "Registration Statement"), filed by the
Company with the Securities and Exchange Commission under the Securities Act of
1933 on the date hereof, relating to the registration of an additional 6,000,000
shares of its Common Stock, $0.001 par value (the "Shares") issuable pursuant to
the Company's 1999 Stock Option Plan, as amended (the "Plan").

     In so acting, we have examined originals or copies (certified or otherwise
identified to our satisfaction) of the Registration Statement and such corporate
records, agreements, documents and other instruments, and such certificates or
comparable documents of public officials and officers and representatives of the
Company, and have made such inquiries of such officers and representatives, as
we have deemed relevant and necessary as a basis for the opinions hereinafter
set forth.

     In such examination, we have assumed the genuineness of all signatures, the
legal capacity of all natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified, conformed or photostatic copies and the
authenticity of the originals of such latter documents. As to all questions of
fact material to this opinion that have not been independently established, we
have relied upon certificates or comparable documents of officers and
representatives of the Company.

     Based on the foregoing, and subject to the qualifications stated herein, we
are of the opinion that the Shares have been duly authorized and, when issued
and sold in accordance with the terms and the Plan, will be validly issued,
fully paid, and nonassessable.

     We hereby consent to the filing of a copy of this letter with the
Securities and Exchange Commission as an exhibit to the Registration Statement.

     The opinions expressed herein are limited solely to the corporate laws of
the State of Nevada, and we express no opinion as to the effect on the matters
covered by this letter of the laws of any other jurisdiction. The opinions
expressed herein are based upon the law and the other matters in effect on the
date hereof, and we assume no obligation to review or supplement this opinion
should such law be changed by legislative action, judicial decision, or
otherwise, or should any facts or other matters upon which we have relied be
changed.


                                        Very truly yours,

                                        /s/ Snell & Wilmer L.L.P.

                                        Snell & Wilmer L.L.P.