Exhibit 4.6

                        AMENDMENT TO M.S. CARRIERS, INC.
                           INCENTIVE STOCK OPTION PLAN

     WHEREAS, the M.S. Carriers, Inc. Incentive Stock Option Plan (the "Plan")
was adopted by M.S. Carriers, Inc. (the "Company") on February 28, 1986, under
which options may be granted from time to time to eligible employees of the
Company;

     WHEREAS, the Company desires to amend the Plan in order to provide for
continued disinterested administration of the Plan to allow for grants of
options under the Plan to be exempt from Section 16(b) of the Securities
Exchange Act of 1934; and

     WHEREAS, the Company desires to document the prior elimination of any
restriction on the transfer of shares purchased under the Plan.

     NOW, THEREFORE, the M.S. Carriers, Inc. Incentive Stock Option Plan is
hereby amended in the following manner:

                                       I.

     Section 2. ADMINISTRATION OF THE PLAN. is hereby deleted in its entirety
and the following is substituted in its place:

     2. ADMINISTRATION. The Plan shall be administered by the members of the
Executive Compensation Committee of the Board of Directors who are not employees
of the Company (the "Committee"), which committee shall consist of not less than
two members. Meetings will beheld at such times and places as shall be
determined by the Committee. A majority of the members of the Committee shall
constitute a quorum for the transaction of business, and the vote of a majority
of those members present at any meeting shall decide any question brought before
that meeting. In addition, the Committee may take any action otherwise proper
under the Plan by the unanimous written consent of its members. No member of the
Committee shall be liable for any act or omission of any other member of the
Committee or for any act or omission on his own part, including but not limited
to, the exercise of any power or discretion given to him under the Plan, except
those resulting from his own gross negligence or willful misconduct. All
questions of interpretation and application of the Plan, or of options granted
hereunder shall be subject to the determination, which shall be final and
binding, of a majority of the Committee.

                                       II.

     Section 13. RESTRICTION ON TRANSFER OF SHARES. is hereby deleted in its
entirety.

     IN WITNESS WHEREOF, this Amendment has been executed this 11th day of
December, 1995.

                                        M.S. Carriers, Inc.


                                        By: /s/ M. J. Barrow
                                            ------------------------------------
                                            M. J. Barrow, Secretary