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                                                                     EXHIBIT 4.2

                     AMENDMENT TO FIRST AMENDED AND RESTATED
                                RIGHTS AGREEMENT

         THIS AMENDMENT TO FIRST AMENDED AND RESTATED RIGHTS AGREEMENT (this
"Amendment"), dated as of April 4, 2003, is between ARKANSAS BEST CORPORATION, a
Delaware corporation (the "Company"), and LASALLE BANK NATIONAL ASSOCIATION (the
"Rights Agent"), at the direction of the Company.

         WHEREAS, the Company and Computershare Investor Services, LLC, the
predecessor Rights Agent, entered into a First Amended and Restated Rights
Agreement dated as of May 1, 2001 (the "Rights Agreement");

         WHEREAS, Section 26 of the Rights Agreement permits the amendment of
the Rights Agreement by the Board of Directors of the Company;

         WHEREAS, pursuant to a resolution duly adopted on March 17, 2003, the
Board of Directors of the Company has duly adopted and authorized the amendment
of the Rights Agreement to amend the definition of "Acquiring Person" to address
the impact of acquisitions of Common Shares (as defined in the Rights Plan) by
the Company; and

         WHEREAS, the Board of Directors of the Company resolved and determined
that such amendment is in the best interest of the Company and consistent with,
and for the purpose of fulfilling, the objectives of the Board of Directors in
connection with the original adoption of the Rights Agreement;

         NOW, THEREFORE, the Rights Agreement is hereby amended as follows:

         1. AMENDMENT OF SECTION 1(a). Section 1(a) of the Rights Agreement is
hereby amended in its entirety to read as follows:

                  (a) "Acquiring Person" means any Person that, together with
         all Affiliates and Associates of such Person, shall be the Beneficial
         Owner of 15% or more of the Common Shares then outstanding. The term
         "Acquiring Person" shall not include the Company, any Subsidiary of the
         Company or any Person who acquires beneficial ownership of the Common
         Shares in a Permitted Transaction, any employee benefit plan of the
         Company or any Subsidiary of the Company or any Person holding Common
         Shares for or pursuant to the terms of any such plan. Notwithstanding
         the foregoing, from and after January 22, 2003 no Person shall become
         an "Acquiring Person" as the result of an acquisition of Common Shares
         by the Company which, by reducing the number of shares outstanding,
         increases the proportionate number of shares beneficially owned by such
         Person to 15% or more of the Common Shares of the Company then
         outstanding; provided, however, that, if a Person shall become the
         Beneficial Owner of 15% or more of the Common Shares of the Company
         then outstanding by reason of share purchases by the Company and shall,
         after such share purchases by the Company and at a time when such
         Person is the Beneficial Owner of 15% or more of the Common Shares of
         the Company then outstanding (as such number has most recently been
         disclosed by the Company in any filing

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         with the Securities and Exchange Commission or other widely
         disseminated public disclosure) become the Beneficial Owner of any
         additional Common Shares of the Company, then such Person shall be
         deemed to be an "Acquiring Person." Notwithstanding the foregoing, if,
         upon Board Approval, the Company determines in good faith that a Person
         who would otherwise be an "Acquiring Person," as defined pursuant to
         the foregoing provisions of this paragraph has become such
         inadvertently, and such Person divests as promptly as practicable a
         sufficient number of Common Shares so that such Person would no longer
         be an Acquiring Person, as defined pursuant to the foregoing provisions
         of this paragraph, then such Person shall not be deemed to be an
         "Acquiring Person" for any purposes of this Agreement.

         2. EFFECTIVENESS.

                  This Amendment to the Rights Agreement shall be effective as
of the date of this Amendment, and all references to the Rights Agreement shall,
from and after such time, be deemed to be references to the Rights Agreement as
amended hereby.

         3. CERTIFICATION.

                  The undersigned officer of the Company certifies by execution
hereof that this Amendment is in compliance with the terms of Section 26 of the
Rights Agreement.

         4. MISCELLANEOUS.

                  This Amendment may be executed in any number of counterparts,
each of such counterparts shall for all purposes be deemed to be an original,
and all such counterparts shall together constitute but one and the same
instrument. If any term, provision, covenant or restriction of this Amendment is
held by a court of competent jurisdiction or other authority to be invalid,
illegal, or unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.

                            [SIGNATURE PAGE FOLLOWS]

                                      -2-
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                  IN WITNESS WHEREOF, the parties hereto have caused this
Amendment to be duly executed as of the date and year first above written.

                                       ARKANSAS BEST CORPORATION

                                       By: /s/ Richard F. Cooper
                                           ----------------------------------
                                       Name:  Richard F. Cooper
                                       Title: Vice President - Administration

                                       LASALLE BANK NATIONAL ASSOCIATION

                                       By: /s/ Mark F. Rimkus
                                           ------------------------------------
                                       Name:  Mark F. Rimkus
                                             ----------------------------------
                                       Title:  Vice President
                                              ---------------------------------

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                                                                    EXHIBIT 10.1

                                  AMENDMENT TO
                         EXECUTIVE PROTECTION AGREEMENT

         This Amendment is entered into as of the ___ day of _________, 2003 by
and between ProLogis (formerly ProLogis Trust), a Maryland real estate
investment trust (the "Trust"), and __________ (the "Executive").

                                   WITNESSETH:

         WHEREAS, the Trust and the Executive are parties to an Executive
Protection Agreement dated as of ______________ (the "Agreement"); and

         WHEREAS, the parties desire to amend certain provisions of the
Agreement as herein provided.

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereby amend the Agreement as follows:

         1. Section 3 of the Agreement is hereby deleted in its entirety and
replaced with the following:

                  "3. Change in Control. For purposes of this Agreement, a
         "Change in Control" means the happening of any of the following:

         (a) The consummation of a transaction, approved by the shareholders of
         the Trust, to merge the Trust into or consolidate the Trust with
         another entity, sell or otherwise dispose of all or substantially all
         of its assets or adopt a plan of liquidation, provided, however, that a
         Change in Control shall not be deemed to have occurred by reason of a
         transaction, or a substantially concurrent or otherwise related series
         of transactions, upon the completion of which 50% or more of the
         beneficial ownership of the voting power of the Trust, the surviving
         corporation or corporation directly or indirectly controlling the Trust
         or the surviving corporation, as the case may be, is held by the same
         persons (as defined below) (although not necessarily in the same
         proportion) as held the beneficial ownership of the voting power of the
         Trust immediately prior to the transaction or the substantially
         concurrent or otherwise related series of transactions, except that
         upon the completion thereof, employees or employee benefit plans of the
         Trust may be a new holder of such beneficial ownership.

         (b) The "beneficial ownership" (as defined in Rule 13d-3 under the
         Securities Exchange Act of 1934, as amended (the "Exchange Act")) of
         securities representing 50% or more of the combined voting power of the
         Trust is acquired, other than from the Trust, by any "person" as
         defined in Sections 13(d) and 14(d) of the Exchange Act (other than any
         trustee or other fiduciary holding securities under an employee benefit
         or other similar stock plan of the Trust).

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         (c) At any time during any period of two consecutive years, individuals
         who at the beginning of such period were members of the Board of
         Trustees of the Trust cease for any reason to constitute at least a
         majority thereof (unless the election, or the nomination for election
         by the Trust's shareholders, of each new trustee was approved by a vote
         of at least two-thirds of the trustees still in office at the time of
         such election or nomination who were trustees at the beginning of such
         period).

         For purposes of this Agreement, the following terms shall be defined as
         indicated:

         (i) The term "Beneficial Owner" shall mean beneficial owner as defined
         in Rule 13d-3 under the Exchange Act.

         (ii) Entities shall be treated as being under "common control" during
         any period in which they are "affiliates" of each other as that term is
         defined in the Exchange Act.

         (iii) The term "person" shall be as defined in Sections 13(d) and 14(d)
         of the Exchange Act, but shall exclude any trustee or other fiduciary
         holding securities under an employee benefit or other similar stock
         plan of the Trust.

         (iv) The term "ProLogis Affiliate" shall mean ProLogis and any of its
         "affiliates" as that term is defined in the Exchange Act."

         2. Capitalized terms used in this Amendment but not specifically
defined herein shall have the meanings ascribed thereto in the Agreement.

         3. Except as otherwise specifically modified hereby, the Agreement
shall remain in full force and effect.

         4. This Amendment shall be governed by, and construed and enforced in
accordance with, the laws of the State of Maryland.

         5. This Amendment may be executed in any number of counterparts, each
of which may be deemed an original and all of which together shall constitute
one and the same instrument.

                  [Remainder of Page Intentionally Left Blank]

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         IN WITNESS WHEREOF, the Executive has hereunto set his hand and,
pursuant to the authorization of its Board of Trustees, the Trust has caused
this Amendment to be executed in its name and on its behalf, all as of the date
first above written.

                                    EXECUTIVE

                                    -----------------------------------

                                    PROLOGIS

                                    By:
                                             --------------------------
                                             Edward S. Nekritz
                                             Managing Director

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