Document:

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                                                                     EXHIBIT 4.1

                            ARKANSAS BEST CORPORATION
                                  NONQUALIFIED
                                STOCK OPTION PLAN

1.       Purpose

         The purpose of the Arkansas Best Corporation Nonqualified Stock Option
Plan (hereinafter called the "Plan") is to advance the interests of Arkansas
Best Corporation (hereinafter called the "Company") by strengthening the ability
of the Company to attract and retain key personnel of high caliber through
encouraging a sense of proprietorship by means of stock ownership.

         The options granted under this Plan are not intended to qualify as
"incentive stock options" pursuant to Section 422 of the Internal Revenue Code
of 1986 (the "Code"), and will, therefore, constitute nonqualified stock
options.

2.       Definitions

         As used in this Plan, and in any Option Agreement, as hereinafter
defined, the following terms shall have the following meanings, unless the
context otherwise requires:

                  (a) "Common Stock" shall mean the Common Stock of the Company,
         par value $.01 per share.

                  (b) "Date of Grant" shall mean the date on which a
         nonqualified stock option is granted pursuant to this Plan.

                  (c) "Fair Market Value" shall mean the closing sale price (or
         average of the quoted closing bid and asked prices if there is no
         closing sale price reported) of the Common Stock on the date specified
         as reported by NASDAQ National Market System or by the principal
         national stock exchange on which the Common Stock is then listed. If
         there is no reported price information for such date, the Fair Market
         Value will be determined by the reported price information for the
         Common Stock on the day nearest preceding such date.

                  (d) "Optionee" shall mean the person to whom an option is
         granted under the Plan or who has obtained the right to exercise an
         option in accordance with the provisions of the Plan.

                  (e) "Plan Adoption Date" means April 19, 2000, the date on
         which the Plan was adopted by the Board of Directors of the Company.

                  (f) "Subsidiary" shall mean any now existing or hereinafter
         organized or acquired corporation of which more than fifty percent
         (50%) of the issued and outstanding voting stock is owned or controlled
         directly or indirectly by the Company or through one or more
         Subsidiaries of the Company.

                                     Page 1
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3.       Shares Subject to the Plan

         The aggregate amount of Common Stock for which options may be granted
under this Plan shall not exceed one million (1,000,000) shares of Common Stock,
which amount may be increased or decreased by the Board of Directors pursuant to
its amendment authority under Section 13 of the Plan. Such shares may be
authorized and previously unissued shares or previously issued shares that have
been reacquired by the Company. Any shares subject to unexercised portions of
the options granted under this Plan which shall have terminated, been canceled
or expired may again be subject to options under this Plan.

4.       Administration

         The Plan shall be administered by the Board of Directors or, at the
option of the Board of Directors, a committee of two or more individuals
appointed by the Board of Directors of the Company (the group responsible for
administering the Plan is referred to herein as the "Committee"). Options may be
granted under this Section 4 by the members of the Committee. Stock Option
Agreements ("Option Agreements"), in the form as approved by the Committee, and
containing such terms and conditions not inconsistent with the provisions of
this Plan as shall have been determined by the Committee, may be executed on
behalf of the Company by the Chairman of the Board, the President or any Vice
President of the Company. The Committee shall have complete authority to
construe, interpret and administer the provisions of the Plan and the provisions
of the Option Agreements relating to options granted hereunder; to prescribe,
amend and rescind rules and regulations pertaining to the Plan; and to make all
other determinations necessary or deemed advisable in the administration of the
Plan. The determinations, interpretations and constructions made by the
Committee shall be final and conclusive.

5.       Eligibility

         Nonqualified stock options to purchase Common Stock may be granted
under Section 4 of the Plan to such key employees or directors of the Company or
its Subsidiaries as shall be determined by the Committee. The Committee shall
determine which persons are to be granted options under Section 4 of the Plan,
the number of options, the number of shares subject to each option, the exercise
price or prices of each option, the vesting and exercise period of each option,
whether an option may be exercised as to less than all of the Common Stock
subject thereto, and such other terms and conditions of each option, if any, as
are not inconsistent with the provisions of this Plan. In addition, the
Committee may, in its sole discretion, provide for vesting of stock options to
accelerate upon a change in control of the Company and enable an employee to
"put" the excess of the fair market value over the exercise price of the options
to the Company in the event of a change in control.

                                     Page 2
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6.       Exercise Price

         The purchase price or prices for Common Stock subject to an option (the
"Exercise Price") granted pursuant to Section 4 of the Plan shall be determined
by the Committee at the Date of Grant.

7.       Term of Stock Options and Limitations on Right to Exercise

         The term of stock options granted pursuant to Section 4 of this Plan
shall be set by the Committee and stated in the option agreement, but in no
event shall any stock option granted under this Plan be exercisable more than
ten years after its Date of Grant. The Company shall not be required to issue
any fractional shares upon the exercise of any options granted under this Plan.
No Optionee nor his legal representatives, legatees or distributees, as the case
may be, will be, or will be deemed to be, a holder of any shares subject to an
option unless and until said option has been exercised and the purchase price of
the shares in respect of which the option has been exercised has been paid. An
option shall not be exercisable except by the Optionee or by a person who has
obtained the Optionee's rights under the option by will or under the laws of
descent and distribution.

8.       Termination of Employment

         The Committee shall determine at the Date of Grant what conditions
shall apply to the exercise of an option granted under Section 4 in the event an
Optionee shall cease to be employed by the Company or a Subsidiary for any
reason. In the event of the death of an Optionee while in the employ or while
serving as a director of the Company or a Subsidiary, the option theretofore
granted to him shall be exercisable by the executor or administrator of the
Optionee's estate, or if the Optionee's estate is not in administration, by the
person or persons to whom the Optionee's right shall have passed under the
Optionee's will or under the laws of descent and distribution, within such
period as may be specified in the Option Agreement, but in no case later than
the expiration date of such option. Neither this Plan nor any option granted
hereunder is intended to confer upon any Optionee any rights with respect to
continuance of employment or other utilization of his services by the Company or
by a Subsidiary, nor to interfere in any way with his right or that of his
employer to terminate his employment or other services at any time (subject to
the terms of any applicable contract).

9.       Dilution or Other Adjustments

         In the event that there is any change in the Common Stock subject to
this Plan or subject to options granted hereunder as the result of any stock
dividend on, dividend of or stock split or stock combination of, or any like
change in, stock of the same class or in the event of any change in the capital
structure of the Company, the Board of Directors or the Committee shall make
such adjustments with respect to options, or any provisions of the Plan, as it
deems appropriate to prevent dilution or enlargement of option rights.

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10.      Expiration and Termination of the Plan

         Options may be granted at any time under Section 4 of the Plan prior to
the tenth anniversary of the Plan Adoption Date, as long as the total number of
shares which may be issued pursuant to options granted under this Plan does not
(except as provided in Section 9 above) exceed the limitations of Section 3
above. This Plan may be abandoned, suspended or terminated at any time by the
Board of Directors of the Company except with respect to any options then
outstanding under the Plan.

11.      Restrictions on Issuance of Shares

                  (a) The Company shall not be obligated to sell or issue any
         shares upon the exercise of any option granted under this Plan unless:

                           (i) the shares with respect to which such option is
                  being exercised have been registered under applicable federal
                  securities laws or are exempt from such registration;

                           (ii) the prior approval of such sale or issuance has
                  been obtained from any state regulatory body having
                  jurisdiction; and

                           (iii) in the event the Common Stock has been listed
                  on any exchange, the shares with respect to which such option
                  is being exercised have been duly listed on such exchange in
                  accordance with the procedure specified therefor.

If the shares to be issued upon the exercise of any option granted under the
Plan are intended to be issued by the Company in reliance upon the exemptions
from the registration requirements of applicable federal securities laws, the
Optionee, if so requested by the Company, shall furnish to the Company such
evidence and representations, including an opinion of counsel, satisfactory to
it, as the Company may reasonably request.

                  (b) No option granted pursuant to the Plan shall be
         transferable by the Optionee other than by will or the laws of descent
         and distribution or between spouses or incident to divorce within the
         meaning of Section 1041 of the Code or any successor provision.

                  (c) Any Common Stock issued to an officer or director of the
         Company pursuant to the exercise of an option granted pursuant to the
         Plan shall not be transferred until at least six (6) months have
         elapsed from the date of grant of such option to the date of
         disposition of the Common Stock underlying such option.

                  (d) The Board of Directors or Committee may impose such other
         restrictions on the ownership and transfer of shares issued pursuant to
         this Plan as it deems desirable; any such restrictions shall be set
         forth in any Option Agreement entered into hereunder.

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12.      Proceeds

         The proceeds to be received by the Company upon exercise of any option
granted under this Plan may be used for any proper purposes.

13.      Amendment of the Plan

         The Board of Directors may amend the Plan from time to time in such
respects as it may deem advisable in its sole discretion or in order that the
options granted hereunder shall conform to any change in applicable laws,
including tax laws, or in regulations or rulings of administrative agencies or
in order that options granted or stock acquired upon exercise of such options
may qualify for simplified registration under applicable securities or other
laws.

14.      Payment Upon Exercise

         Upon the exercise of any option granted under the Plan, the company may
make financing available to the Optionee for the purchase of the Common Stock
that may be acquired pursuant to the exercise of such option on such terms as
the Committee shall specify. An Optionee may pay the Exercise Price of the
shares of Common Stock as to which an option is being exercised by the delivery
of cash, a certified cashier's check or by the delivery of shares of Common
Stock having a Fair Market Value on the date of exercise equal to the Exercise
Price.

         Any option granted under the Plan may be exercised by a broker-dealer
acting on behalf of an Optionee if (a) the broker-dealer has received from the
Optionee or the company a fully and duly endorsed agreement evidencing such
option, together with instructions signed by the Optionee requesting the Company
to deliver the shares of Common Stock subject to such option to the
broker-dealer on behalf of the Optionee and specifying the account into which
such shares should be deposited, (b) adequate provision has been made with
respect to the payment of any withholding taxes due upon such exercise, and (c)
the broker-dealer and the Optionee have otherwise complied with Section
220.3(e)(r) of Regulation T, 12 CFR Part 220, or any successor provision.

         IN WITNESS WHEREOF, Arkansas Best Corporation, acting by and through
its officers hereunto duly authorized, has executed this Plan, to be effective
on the Plan Adoption Date.

                                    ARKANSAS BEST CORPORATION

                                    By:
                                        -------------------------------------
                                         Name:
                                              -------------------------------
                                         Its:
                                              -------------------------------

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<PAGE>   6

                              AMENDMENT NUMBER ONE
                                     TO THE
                            ARKANSAS BEST CORPORATION
                         NONQUALIFIED STOCK OPTION PLAN

         THIS AMENDMENT is made effective the 1st day of January, 2001, by
ARKANSAS BEST CORPORATION, a Delaware Corporation (the "Company"),

                                   WITNESSETH:

         WHEREAS, effective April 19, 2000, the Company established the Arkansas
Best Corporation Nonqualified Stock Option Plan (the "Plan");

         WHEREAS, the Company desires to amend the Plan to eliminate the
provision that allows the Company to provide financing to optionees to purchase
shares of stock of the Company upon the exercise of options granted under the
Plan; and

         WHEREAS, the Board of Directors may amend the Plan in accordance with
Section 13 of the Plan.

         NOW, THEREFORE, the Plan is hereby amended as follows:

1.       The first paragraph of Section 14 of the Plan is deleted in its
         entirety and replaced with the following:

         "An Optionee may pay the Exercise Price of the shares of Common Stock
         as to which an option is being exercised by the delivery of cash, a
         certified cashier's check or by the delivery of shares of Common Stock
         having a Fair Market Value on the date of exercise equal to the
         Exercise Price."

         IN WITNESS WHEREOF, this amendment has been executed by a duly
authorized officer on this 29th day of December, 2000.

                                    ARKANSAS BEST CORPORATION

                                    By:
                                        --------------------------------
                                        Richard F. Cooper
                                        Vice President of Administration<PAGE>   1
PORTIONS OF THIS EXHIBIT IDENTIFIED BY "***" HAVE BEEN DELETED PURSUANT TO A
REQUEST FOR CONFIDENTIAL TREATMENT FILED WITH THE SECURITIES AND EXCHANGE
COMMISSION UNDER RULE 24b-2 OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED,
AND THE FREEDOM OF INFORMATION ACT.

                                                                 EXHIBIT 10(b)-1

                            BAY GAS STORAGE CO., LTD.

                                  P.O. Box 1368
   Telephone                  Mobile, Alabama 36633                 Fax
(334) 476-2720                                                 (334) 478-5817

                                  July 19, 2000

Mr. Alan Kilpatrick
Southern Company Services, Inc.
600 N. 18th Street
Birmingham, AL 35291

Re:  Modification of the Storage Service Agreement FSMC99, date April 1, 1999,
     between Bay Gas Storage Company, Ltd. and Southern Company Services, Inc.
     (the "Contract")

Dear Alan:

Southern Company Services, Inc. as Agent for Alabama Power Company, Georgia
Power Company, Gulf Power Company, Mississippi Power Company and Savannah
Electric and Power Company ("Southern Company") and Bay Gas Storage Company,
Ltd. ("Bay Gas") (collectively referred to herein as "Parties") have executed
the above-referenced Contract under which Bay Gas provides certain natural gas
storage services to Southern Company. The Parties wish to modify the Contract to
include the following provisions:

Beginning April 1, 2001 and continuing for the term of the Contract, quantities
as shown in Article 1.1 shall be amended to read as follow:

     (a)  Firm Withdrawal - a Firm Maximum Daily Withdrawal Quantity ("FMDWQ")
          of *** MMBtu per day and;

          Interruptible Withdrawal - an Interruptible Maximum Daily Withdrawal
          Quantity ("IMDWQ") of *** MMBtu per day;

<PAGE>   2

     (b)  Firm Storage - a Firm Maximum Storage Quantity (" FMSQ") in the
          Storage Facilities equal to *** MMBtu.

     (c)  Firm Injection - a Firm Maximum Daily Injection Quantity ("FMDIQ") of
          *** MMBtu per day and;

          Interruptible Injection - an Interruptible Maximum Daily Injection
          Quantity ("IMDIQ") of *** MMBtu per day.

In addition, beginning April 1, 2001 and continuing for the term of the
Contract, the Exhibit "A" attached hereto will replace the existing Exhibit "A".
All other terms and conditions of the Contract remain in effect.

The Parties have negotiated a separate storage service agreement (Number FMSE00,
dated August 1, 2000) and agree to execute this modification contemporaneously
with the execution of the separate storage service agreement number FMSE00.

If the provisions described herein are agreeable to Southern Company, please
signify your acceptance by executing two originals of this letter and returning
both to my attention. I will forward one fully executed original for your files.

Thank you for your help in this matter.

                                                 Sincerely,

                                                 /s/ Greg Welch

                                                 Greg Welch
                                                 Director - Storage Marketing

Southern Company Services, Inc., as agent      MGS Storage Services, Inc.
for Alabama Power Company, Georgia Power       General Partner of
Company, Mississippi Power Company, and        Bay Gas Storage Company, Ltd.
Savannah Electric and Power Company

By: /s/ A. J. Topazi                           By:  /s/ W. G. Coffeen, III

Title:  Vice President                         Title:  Vice President

Agreed and accepted this                       Agreed and accepted this
24th day of  July 2000                         1st day of August 2000

<PAGE>   3

                                   EXHIBIT "A"

TO STORAGE AGREEMENT ("CONTRACT") BETWEEN BAY GAS STORAGE
COMPANY, LTD. AND SOUTHERN COMPANY SERVICES, INC.

<TABLE>
<CAPTION>
                                                                                         MINIMUM
POINT(S) OF RECEIPT                                  INJECTION QUANTITY                 PRESSURE
-------------------                                  ------------------                 --------
                                                          (MMBtus)                       (PSIG)
<S>                                                  <C>                               <C>
Interconnection between the Storage
Facilities and the pipeline facilities of
FGT in Mobile County, Alabama                               ***                            625
(Interconnect ID: BG- 1002)

Interconnection between the Storage
Facilities and the pipeline facilities of
KOCH GATEWAY  in Mobile County, Alabama                     ***                            575
(Interconnect ID: BG-1003)
</TABLE>

Gas may be scheduled for delivery at either or all of the Points of Receipt, in
quantities up to the maximum quantities indicated for each such Point, but the
cumulative total of deliveries at all Points of Receipt shall not exceed the
maximum quantity indicated for any single Point, unless otherwise agreed by
Company.

<TABLE>
<CAPTION>
                                                                                         FMDWQ
                                                                                       --------
                                                                                       (MMBtus)
<S>                                                                                  <C>
POINT(S) OF DELIVERY
Interconnection between the Storage Facilities and
the pipeline facilities of FGT in Mobile County, Alabama                                  ***
(Interconnect ID: BG-1002)

Interconnection between the Storage Facilities and
the pipeline facilities of KOCH GATEWAY  in
Mobile County, Alabama                                                                    ***
(Interconnect ID: BG-1003)

Interconnection between the Storage
Facilities and the facilities of FGT at
Olin in Washington County, Alabama                                                        ***
(Interconnect ID: BG-1005)

The weld connection between the Storage Facilities and Alabama Power Company's
pipeline downstream of the Bay Gas metering facility at Plant Barry in
Mobile County, Alabama  (Interconnect ID: BG-1006)                                        ***
</TABLE>

Gas may be scheduled for delivery at either or all of the Points of Delivery, in
quantities up to the maximum quantities indicated for each such Point, but the
cumulative total of deliveries at all Points of Delivery shall not exceed the
maximum quantity indicated for any single Point, unless otherwise agreed by
Company.

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