<PAGE>
 
                                                                   Exhibit 10.58

                              EMPLOYMENT AGREEMENT

          AGREEMENT, dated as of February 10, 1999, by and between Petro
Stopping Centers, L.P., a Delaware limited partnership (the "Company") and James
A. Cardwell, Jr. ("Executive").

          IN CONSIDERATION of the premises and the mutual covenants set forth
below, the parties hereby agree as follows:

          1.  Employment.  The Company hereby agrees to employ Executive as
              ----------
Senior Vice President of the Company, and Executive hereby accepts such
employment, on the terms and conditions hereinafter set forth.

          2.  Term.  The period of employment of Executive by the Company
              ----
hereunder (the "Employment Period") shall commence on February 10, 1999 (the
"Commencement Date") and shall end on the third anniversary thereof. The
Employment Period may be sooner terminated by either party in accordance with
Section 6 of this Agreement.

          3.  Position and Duties.  During the Employment Period, Executive
              -------------------
shall serve as an executive of the Company, and shall report directly to the
President of the Company. Executive shall devote substantially all of his
working time, attention and energies during normal business hours (other than
absences due to illness or vacation) to the performance of his duties for the
Company. Notwithstanding the above, Executive shall be permitted, to the extent
such activities do not substantially interfere with the performance by Executive
of his duties and responsibilities hereunder or violate Section 10 of this
Agreement, to (i) manage Executive's personal, financial and legal affairs, and
(ii) to serve on civic or charitable boards or committees (it being expressly
understood and agreed that Executive's continuing to serve on any such board
and/or committees on which Executive is serving, or with which Executive is
otherwise associated, as of the Commencement Date (each of which has been
disclosed to the Company prior to the execution of this Agreement or will be
disclosed promptly thereafter), shall be deemed not to interfere with the
performance by Executive of his duties and responsibilities under this
Agreement).

          4.  Place of Performance.  The principal place of employment of
              --------------------
Executive shall be at the Company's principal executive offices in El Paso,
Texas or such other place as the Board of Directors of the Company (the "Board")
may determine.
<PAGE>
 
     5.   Compensation and Related Matters.
          -------------------------------- 

     (a)  Base Salary.  During the Employment Period, the Company shall pay
          -----------
Executive a base salary at the rate of not less than $180,000 per year ("Base
Salary"). Executive's Base Salary shall be paid in approximately equal
installments in accordance with the Company's customary payroll practices.
Executive's Base Salary shall be subject to annual review by the compensation
committee of the Board for possible increase. If Executive's Base Salary is
increased by the Company, such increased Base Salary shall then constitute the
Base Salary for all purposes of this Agreement. Executive's Base Salary shall
not be decreased at any time during the Employment Period without his direct
written consent.

     (b)  Incentive Compensation.
          ----------------------

          (i)   Beginning with calendar year 1999, Executive shall annually be
     eligible to receive a bonus (the "Bonus") pursuant to a schedule to be
     mutually agreed upon between the Company and Executive, provided, that, the
                                                             --------  ----
     amount of such Bonus and the performance criteria relating thereto shall be
     no less favorable than those set forth on Schedule A hereof.

          (ii)  Each Bonus shall be paid 10 days following the rendering of
     audited financial statements for the relevant calendar year (the "Payment
     Date").

     (c)  Expenses.  The Company shall promptly reimburse Executive for all
          --------
reasonable business expenses upon the presentation of reasonably itemized
statements of such expenses in accordance with the Company's policies and
procedures now in force or as such policies and procedures may be modified with
respect to all senior executive officers of the Company.

     (d)  Vacation.
          -------- 

          (i)   Executive shall be entitled to four (4) weeks vacation per year;

          (ii)  Unused vacation time may be carried forward from one year to the
     next; and

          (iii) Upon the termination of the Employment Period or non-renewal of
     this Agreement, Executive shall be entitled to receive compensation for all
     earned but unused vacation days to the extent permitted by the Company's
     then current policy with respect to all senior executive officers of the
     Company.

     (e)  Services Furnished.  During the Employment Period, the Company shall
          ------------------                                                  
furnish Executive with office space, stenographic and secretarial assistance and
such other facilities and services comparable to those provided to the Company's
other senior executive officers.

     (f)  Welfare, Pension and Incentive Benefit Plan.  During the Employment
          -------------------------------------------
Period, Executive (and his spouse and dependents to the extent provided therein)
shall be entitled to 

                                       2
<PAGE>
 
participate in and be covered under all the welfare benefit plans or programs
maintained by the Company from time to time for the benefit of its senior
executives, including, without limitation, the executive medical program, and
all medical, hospitalization, dental, disability, accidental death and
dismemberment and travel accident insurance plans and programs In addition,
during the Employment Period, Executive shall be eligible to participate in all
pension, retirement, savings and other employee benefit plans and programs
maintained from time to time by the Company for the benefit of its senior
executives.

     (g)  Other Benefits.  During the Employment Period, the Company shall
          --------------
provide Executive with the benefits described below:

          (i)   The Company will pay Executive's portable life and disability
     insurance;

          (ii)  Executive will participate in any other Company equity incentive
     plan adopted by the Company during the term of this Agreement; and

          (iii) Membership dues for membership at a country club of Executive's
     choosing in an amount not to exceed $4,000 annually.

     6.   Termination.  Executive's employment hereunder shall terminate upon
          -----------
the expiration of the Employment Period and may be terminated during the
Employment Period under the following circumstances:

     (a)  Death.  Executive's employment hereunder shall terminate upon his
          -----
death.

     (b)  Disability.  If, as a result of Executive's incapacity due to physical
          ----------
or mental illness, Executive shall have been substantially unable to perform his
duties hereunder for an entire period of four (4) months or more during any six
(6) consecutive month period, and within thirty (30) days after written Notice
of Termination is given after such six (6) month period, Executive shall not
have returned to the substantial performance of his duties on a fulltime basis,
the Company shall have the right to terminate Executive's employment hereunder
for "Disability", and such termination in and of itself shall not be, nor shall
it be deemed to be, a breach of this Agreement.

     (c)  Cause.  The Company shall have the right to terminate Executive's
          -----                                                            
employment for Cause, and such termination in and of itself shall not be, nor
shall it be deemed to be, a breach of this Agreement. For purposes of this
Agreement, the Company shall have "Cause" to terminate Executive's employment
upon Executive's:

          (i)  Conviction of, or plea of guilty or nolo contendere to, a felony;
     or

          (ii) Continued failure to use reasonable best efforts to substantially
     perform his duties hereunder (other than such failure resulting from
     Executive's incapacity due to physical or mental illness or subsequent to
     the issuance of a Notice of Termination by Executive for Good Reason) after
     demand for substantial performance is delivered by the Company in writing
     that specifically identifies the manner in which the 

                                       3
<PAGE>
 
     Company believes Executive has not used reasonable best efforts to
     substantially perform his duties; or

          (iii) Misconduct (including, but not limited to, a breach of the
     provisions of Section 10) that is materially economically injurious to the
     Company or to any entity in control of, controlled by or under common
     control with the Company ("Affiliates").

     (d)  Good Reason.  Executive may terminate his employment for "Good Reason"
          -----------                                                           
within one hundred and twenty (120) days after Executive has actual knowledge of
the occurrence, without the written consent of Executive, of one of the
following events that has not been cured within thirty (30) days after written
notice thereof has been given by Executive to the Company:

          (i)   A reduction by the Company in Executive's Base Salary or a
     failure by the Company to pay any such amounts when due;

          (ii)  The Company's failure to provide the benefits set forth in
     Section 5 or the failure of the Company to substantially provide any
     material employee benefits due to be provided to Executive (other than any
     such failure not inconsistent with any express provisions contained herein
     which failure affects all senior executive officers); or

          (iii) The Company's failure to provide in all material respects the
     indemnification set forth in Section 11 of this Agreement.

Executive's right to terminate his employment hereunder for Good Reason shall
not be affected by his incapacity due to physical or mental illness.
Executive's continued employment during the one hundred and twenty (120) day
period referred to above in this paragraph (d) shall not constitute consent to,
or a waiver of rights with respect to, any act or failure to act constituting
Good Reason hereunder.

     (e)  Without Cause.  The Company shall have the right to terminate
          -------------
Executive's employment hereunder without Cause by providing Executive with a
Notice of Termination sixty (60) days prior to the date of termination of
employment, and such termination shall not in and of itself be, nor shall it be
deemed to be, a breach of this Agreement.

     (f)  Without Good Reason.  Executive shall have the right to terminate his
          -------------------
employment hereunder without Good Reason by providing the Company with a Notice
of Termination sixty (60) days prior to the date of termination of employment,
and such termination shall not in and of itself be, nor shall it be deemed to
be, a breach of this Agreement.

     7.   Termination Procedure.
          --------------------- 

     (a)  Notice of Termination.  Any termination of Executive's employment by
          ---------------------
the Company or by Executive during the Employment Period (other than termination
pursuant to Section 6(a)) shall be communicated by written Notice of Termination
to the other party hereto in accordance with Section 14. For purposes of this
Agreement, a "Notice of Termination" shall mean a notice which shall indicate
the specific termination provision in this Agreement relied 

                                       4
<PAGE>
 
upon and shall set forth in reasonable detail the facts and circumstances
claimed to provide a basis for termination of Executive's employment under the
provision so indicated.

     (b)  Date of Termination.  "Date of Termination" shall mean (i) if
          -------------------
Executive's employment is terminated by his death, the date of his death, (ii)
if Executive's employment is terminated pursuant to Section 6(b), thirty (30)
days after Notice of Termination (provided that Executive shall not have
returned to the substantial performance of his duties on a full-time basis
during such thirty (30) day period), and (iii) if Executive's employment is
terminated for any other reason, the date on which a Notice of Termination is
given or any later date (within thirty (30) days after the giving of such
notice) set forth in such Notice of Termination.

     8.   Compensation Upon Termination or During Disability.  In the event
          --------------------------------------------------
Executive is disabled or his employment terminates during the Employment Period,
the Company shall provide Executive with the payments and benefits set forth
below. Executive acknowledges and agrees that the payments set forth in this
Section 8 constitute liquidated damages for termination of his employment during
the Employment Period.

     (a)  Termination By Company without Cause or by Executive for Good Reason.
          --------------------------------------------------------------------
If Executive's employment is terminated by the Company without Cause or by
Executive for Good Reason:

          (i)   The Company shall pay to Executive (A) his Base Salary and
     accrued vacation pay through the Date of Termination, as soon as
     practicable following the Date of Termination, and (B) an amount equal to
     one (1) times Executive's current Base Salary; and

          (ii)  The Company shall maintain in full force and effect, for the
     continued benefit of Executive, his spouse and his dependents for a period
     of twelve (12) months following the Date of Termination the medical,
     hospitalization, dental, and life insurance programs in which Executive,
     his spouse and his dependents were participating immediately prior to the
     Date of Termination at the level in effect and upon substantially the same
     terms and conditions (including without limitation contributions required
     by Executive for such benefits) as existed immediately prior to the Date of
     Termination; provided, that, if Executive, his spouse or his dependents
                  --------  ----
     cannot continue to participate in the Company programs providing such
     benefits, the Company shall arrange to provide Executive, his spouse and
     his dependents with the economic equivalent of such benefits which they
     otherwise would have been entitled to receive under such plans and programs
     ("Continued Benefits"), provided, that, such Continued Benefits shall
                             --------  ----
     terminate on the date or dates Executive receives equivalent coverage and
     benefits, without waiting period or pre-existing condition limitations,
     under the plans and programs of a subsequent employer (such coverage and
     benefits to be determined on a coverage by coverage or benefit by benefit,
     basis); and

          (iii) The Company shall reimburse Executive pursuant to Section 5(c),
     for reasonable expenses incurred, but not paid prior to such termination of
     employment; and

                                       5
<PAGE>
 
          (iv)  Executive shall be entitled to any other rights, compensation
     and/or benefits as may be due to Executive in accordance with the terms and
     provisions of any agreements, plans or programs of the Company; and

          (v)   Executive shall be entitled to the Bonus, determined in
     accordance with Section 5(b), for the year in which employment is
     terminated that Executive would have received had he remained employed
     through the Payment Date for such Bonus, pro rated to the Date of
     Termination.

     (b)  Cause or By Executive Without Good Reason.  If Executive's employment
          -----------------------------------------
is terminated by the Company for Cause or by Executive (other than for Good
Reason):

          (i)   The Company shall pay Executive his Base Salary and, to the
     extent required by law or the Company's vacation policy, his accrued
     vacation pay through the Date of Termination, as soon as practicable
     following the Date of Termination; and

          (ii)  The Company shall reimburse Executive pursuant to Section 5(c),
     for reasonable expenses incurred, but not paid prior to such termination of
     employment, unless such termination resulted from a misappropriation of
     Company funds; and

          (iii) Executive shall be entitled to any other rights, compensation
     and/or benefits as may be due to Executive in accordance with the terms and
     provisions of any agreements, plans or programs of the Company.

     (c)  Disability.  During any period that Executive fails to perform his
          ----------
duties hereunder as a result of incapacity due to physical or mental illness
("Disability Period"), Executive shall continue to receive his full Base Salary
set forth in Section 5(a) until his employment is terminated pursuant to Section
6(b); provided, however, that Executive's Base Salary shall be off-set on a
      --------  -------
dollar for dollar basis for each dollar Executive receives from Company provided
disability insurance benefits. In the event Executive's employment is terminated
for Disability pursuant to Section 6(b):

          (i)   The Company shall pay to Executive his Base Salary and accrued
     vacation pay through the Date of Termination, as soon as practicable
     following the Date of Termination; provided, however, that Executive's Base
                                        --------  -------
     Salary shall be off-set on a dollar for dollar basis for each dollar
     Executive receives from Company provided disability insurance benefits; and

          (ii)  The Company shall reimburse Executive pursuant to Section 5(c),
     for reasonable expenses incurred, but not paid prior to such termination of
     employment; and

          (iii) Executive shall be entitled to any other rights, compensation
     and/or benefits as may be due to Executive in accordance with the terms and
     provisions of any agreements, plans or programs of the Company.

     (d)  Death.  If Executive's employment is terminated by his death:
          -----                                                        

                                       6
<PAGE>
 
          (i)   The Company shall pay in a lump sum to Executive's
     beneficiary(ies), legal representative(s) or estate, as the case may be,
     Executive's Base Salary through the Date of Termination and Executive's
     beneficiary(ies), legal representative(s) or estate shall be entitled to
     the Bonus, determined in accordance with Section 5(b), for the year in
     which employment is terminated that Executive would have received had he
     remained employed through the Payment Date for such Bonus, pro-rated to the
     Date of Termination; and

          (ii)  The Company shall reimburse Executive's beneficiary(ies), legal
     representative(s), or estate, as the case may be, pursuant to Section 5(c),
     for reasonable expenses incurred, but not paid prior to such termination of
     employment; and

          (iii) Executive's beneficiary(ies), legal representative(s) or estate,
     as the case may be, shall be entitled to any other rights, compensation and
     benefits as may be due to any such persons or estate in accordance with the
     terms and provisions of any agreements, plans or programs of the Company.

     9.   Mitigation.  Executive shall not be required to mitigate amounts
          ----------
payable under this Agreement by seeking other employment or otherwise, and there
shall be no offset against amounts due Executive under this Agreement on account
of subsequent employment except as specifically provided herein.

     10.  Confidential Information, Ownership of Documents, Non-Competition.
          ----------------------------------------------------------------- 

     (a)  Confidential Information.  Executive shall hold in a fiduciary
          ------------------------
capacity for the benefit of the Company all trade secrets and confidential
information, knowledge or data relating to the Company and its businesses and
investments, which shall have been obtained by Executive during Executive's
employment by the Company and which is not generally available public knowledge
(other than by acts by Executive in violation of this Agreement). Except as may
be required or appropriate in connection with his carrying out his duties under
this Agreement, Executive shall not, without the prior written consent of the
Company or as may otherwise be required by law or any legal process, or as is
necessary in connection with any adversarial proceeding against the Company (in
which case Executive shall use his reasonable best efforts in cooperating with
the Company in obtaining a protective order against disclosure by a court of
competent jurisdiction), communicate or divulge any such trade secrets,
information, knowledge or data to anyone other than the Company and those
designated by the Company or on behalf of the Company in the furtherance of its
business or to perform duties hereunder.

     (b)  Removal of Documents:  Rights to Product.  All records, files,
          ----------------------------------------
drawings, documents, models, equipment, and the like relating to the Company's
business, which Executive has control over shall not be removed from the
Company's premises without its written consent, unless such removal is in the
furtherance of the Company's business or is in connection with Executive's
carrying out his duties under this Agreement and, if so removed, shall be
returned to the Company promptly after termination of Executive's employment
hereunder, or otherwise promptly after removal if such removal occurs following
termination of employment. Executive shall assign to the Company all rights to
trade secrets and other products relating to the 

                                       7
<PAGE>
 
Company's business developed by him alone or in conjunction with others at any
time while employed by the Company.

     (c)  Non-Competition. During the employment of Executive with the Company
          ---------------
pursuant to this Agreement and for the greater of (i) a one year period
following the termination of his employment for any reason or (ii) the period of
time set forth in the Partnership Agreement (as defined below) with respect to
the non-competition and non-solicitation provisions contained therein ((i) and
(ii) collectively referred to as the "Restricted Period"), Executive agrees that
without the Company's prior written consent, which may be withheld in its
absolute discretion, he will not, except as otherwise permitted in the
Partnership Agreement, enter into, be engaged or interested in, as a principal,
stockholder, director, trustee, partner, officer, agent, employee, consultant,
independent contractor, or otherwise, any business or undertaking which directly
compete with the truck stop business of the Company, its affiliates or their
successors within any county where any of the Company, its affiliates, or their
successors are doing business, or has made definite plans for and has taken
steps preparatory to doing business; provided, however, that Employee's
                                     --------  -------                 
ownership of five percent (5%) or less of the capital stock of a public company
that competes with the Company shall not be prohibited by this covenant.

     (d)  Non-Solicitation.  During the employment of Executive with the Company
          ----------------                                                      
pursuant to this Agreement and during the Restricted Period, Executive agrees
that without the Company's prior written consent, which may be withheld in its
absolute discretion, he will not, except as otherwise permitted in the
Partnership Agreement, (i) call upon any person who is, at that time, an
employee of the Company, any of its affiliates or their successors in a
managerial capacity for the purpose or with the intent of enticing such employee
away from or out of the employ of the Company, any of its affiliates or their
successors, or (ii) solicit business from any person or entity which is at that
time a customer of the Company, any of its affiliates or their successors.

     (e)  Injunctive Relief.  In the event of a breach or threatened breach of
          -----------------
this Section 10, Executive agrees that the Company shall be entitled to
injunctive relief in a court of appropriate jurisdiction to remedy any such
breach or threatened breach, Executive acknowledging that damages would be
inadequate and insufficient.

     (f)  Continuing Operation.  Except as specifically provided in this Section
          --------------------
10, the termination of Executive's employment or of this Agreement shall have no
effect on the continuing operation of this Section 10.

     (g)  Reformation.  In the event that any of the provisions of this Section
          -----------
10 are not enforceable in accordance with their terms, Executive and the Company
agree that such Section shall be reformed to make such Section enforceable in a
manner which provides the Company the maximum rights permitted by law.

     11.  Indemnification.
          --------------- 

     (a)  General.  The Company shall, to the extent provided in the Third
          -------
Amended and Restated Limited Partnership Agreement of the Company dated as of
the Closing (the "Partnership Agreement"), and to the maximum extent permitted
by law, indemnify and hold 

                                       8
<PAGE>
 
harmless Executive from any and all losses, damages, claims or expenses that may
be asserted against Executive at any time in connection with his services for
the Company, his employment hereunder or that may otherwise derive from
Executive's employment as contemplated hereby.

     (b)  Insurance.  The Company may, but shall not be required to, maintain
          ---------
such insurance for the protection of its officers and directors as is
appropriate for entities engaged in the Company's business.

     12.  Legal Fees and Expenses.  If any contest or dispute shall arise
          -----------------------
between the Company and Executive regarding any provision of this Agreement, the
Company shall reimburse Executive for all legal fees and expenses reasonably
incurred by Executive in connection with such contest or dispute, but only if
Executive is successful in respect of substantially all of Executive's claims
brought and pursued in connection with such contest or dispute. Such
reimbursement shall be made as soon as practicable following the resolution of
such contest or dispute (whether or not appealed) to the extent the Company
receives reasonable written evidence of such fees and expenses.

     13.  Successors:   Binding Agreement.
          ------------------------------- 

     (a)  Company's Successors.  No rights or obligations of the Company under
          --------------------
this Agreement may be assigned or transferred except that the Company will
require any successor (whether direct or indirect, by purchase, merger,
consolidation or otherwise) to all or substantially all of the business and/or
assets of the Company to expressly assume and agree to perform this Agreement in
the same manner and to the same extent that the Company would be required to
perform it if no such succession had taken place. As used in this Agreement,
"Company" shall mean the Company as herein before defined and any successor to
its business and/or assets (by merger, purchase or otherwise) which executes and
delivers the agreement provided for in this Section 13 or which otherwise
becomes bound by all the terms and provisions of this Agreement by operation of
law.

     (b)  Executive's Successors.  No rights or obligations of Executive under
          ----------------------
this Agreement may be assigned or transferred by Executive other than his rights
to payments or benefits hereunder, which may be transferred only by will or the
laws of descent and distribution. Upon Executive's death, this Agreement and all
rights of Executive hereunder shall inure to the benefit of and be enforceable
by Executive's beneficiary or beneficiaries, personal or legal representatives,
or estate, to the extent any such person succeeds to Executive's interests under
this Agreement. Executive shall be entitled to select and change a beneficiary
or beneficiaries to receive any benefit or compensation payable hereunder
following Executive's death by giving the Company written notice thereof. In the
event of Executive's death or a judicial determination of his incompetence,
reference in this Agreement to Executive shall be deemed, where appropriate, to
refer to his beneficiary(ies), estate or other legal representative(s). If
Executive should die following his Date of Termination while any amounts would
still be payable to him hereunder if he had continued to live, all such amounts
unless otherwise provided herein shall be paid in accordance with the terms of
this Agreement to such person or persons so appointed in writing by Executive,
or otherwise to his legal representative(s) or estate.

                                       9
<PAGE>
 
     14.  Notice.  For the purposes of this Agreement, notices, demands and all
          ------
other communications provided for in this Agreement shall be in writing and
shall be deemed to have been duly given when delivered either personally or by
United States certified or registered mail, return receipt requested, postage
prepaid, addressed as follows:

     If to Executive:

     James A. Cardwell, Jr.
     6080 Surety Drive
     El Paso, Texas
     79905

     If to the Company:

     Petro Stopping Centers, L.P.
     Attention:  General Counsel
     6080 Surety Drive
     El Paso, Texas
     79905

     with a copy to:

     Andrew L. Gaines
     Akin, Gump, Strauss, Hauer & Feld
     590 Madison Avenue
     New York, New York 10022-4616

or to such other address as any party may have furnished to the others in
writing in accordance herewith, except that notices of change of address shall
be effective only upon receipt.

     15.  Miscellaneous.  No provisions of this Agreement may be amended,
          -------------
modified, or waived unless such amendment or modification is agreed to in
writing signed by Executive and by a duly authorized officer of the Company, and
such waiver is set forth in writing and signed by the party to be charged. No
waiver by either party hereto at any time of any breach by the other party
hereto of any condition or provision of this Agreement to be performed by such
other party shall be deemed a waiver of similar or dissimilar provisions or
conditions at the same or at any prior or subsequent time. The respective rights
and obligations of the parties hereunder of this Agreement shall survive
Executive's termination of employment and the termination of this Agreement to
the extent necessary for the intended preservation of such rights and
obligations.

     16.  Counterparts.  This Agreement may be executed in one or more
          ------------
counterparts, each of which shall be deemed to be an original but all of which
together will constitute one and the same instrument.

                                       10
<PAGE>
 
     17.  Entire Agreement.  This Agreement, set forth the entire agreement of
          ----------------
the parties hereto in respect of the subject matter contained herein and
supersede all prior agreements, promises, covenants, arrangements,
communications, representations or warranties, whether oral or written, by any
officer, employee or representative of any party hereto in respect of such
subject matter. Except as otherwise provided herein, any prior agreement of the
parties hereto in respect of the subject matter contained herein is hereby
terminated and cancelled, including, but not limited to, your current employment
agreement with the Company, if any.

     18.  Withholding.  All payments hereunder shall be subject to any required
          -----------                                                          
withholding of Federal, state and local taxes pursuant to any applicable law or
regulation.

     19.  Noncontravention.  The Company represents that the Company is not
          ----------------
prevented from entering into, or performing this Agreement by the terms of any
law, order, rule or regulation, its by-laws or declaration of trust, or any
agreement to which it is a party, other than which would not have a material
adverse effect on the Company's ability to enter into or perform this Agreement.

     20.  Section Headings.  The section headings in this Employment Agreement
          ----------------
are for convenience of reference only, and they form no part of this Agreement
and shall not affect its interpretation.

     21.  Severability.  If this Agreement or any portion thereof is, or the
          ------------                                                      
transactions contemplated hereby are, found to be inconsistent or contrary to
any valid applicable laws or official orders, rules and regulations, the
inconsistent or contrary provision shall be null and void and such laws, orders,
rules and regulations shall control and, as so modified, this Agreement shall
continue in full force and effect; provided, however, that nothing herein
                                   --------  -------
contained shall be construed as a waiver of any right to question or contest any
such law, order, rule or regulation in any forum having jurisdiction.

     22.  Governing Law.  The provisions of this Agreement shall be construed in
          -------------                                                         
accordance with the laws of the State of Texas without regard to its conflict of
law principles.

                                       11
<PAGE>
 
          IN WITNESS WHEREOF, the parties hereto have executed this Agreement on
the date first above written.


                                    PETRO STOPPING CENTERS, L.P.


                                    By:
                                       ---------------------------------------

 
                                    ------------------------------------------
                                    James A. Cardwell, Jr.

                                       12
<PAGE>
 
                                   SCHEDULE A


Incentive Compensation.
---------------------- 

     (a)  The Bonus shall be paid as a percent of Base Salary (as defined in
Section 5(a) of the Employment Agreement), based upon the achievements of Target
EBITDA, as provided in accordance with the following table:

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
                   TARGET EBITDA                       BONUS
                   -------------                       -----
                   <S>                                 <C>
--------------------------------------------------------------------------------
                        90%                             20%
--------------------------------------------------------------------------------
                        95%                             40%
--------------------------------------------------------------------------------
                       100%                             60%
--------------------------------------------------------------------------------
                       105%                             90%
--------------------------------------------------------------------------------
                       110%                             120%
--------------------------------------------------------------------------------
</TABLE>

In accordance with the above table, if EBITDA achieved for any calendar year
exceeds 90% Target EBITDA, but is less than 100% Target EBITDA, the Bonus shall
be such percentage of Base Salary between 20% and 60%, calculated on a straight-
line basis, as corresponds to the relative achievement of EBITDA, with 20%
corresponding to 90% Target EBITDA and 60% corresponding to 100% Target EBITDA.
If EBITDA achieved for any calendar year exceeds 100% Target EBITDA, but is less
than 110% Target EBITDA, the Bonus shall be such percentage of Base Salary
between 60% and 120%, calculated on a straight-line basis, as corresponds to the
relative achievement of EBITDA, with 60% corresponding to 100% Target EBITDA and
120% corresponding to 110% Target EBITDA.  Notwithstanding the foregoing, if
greater than 110% Target EBITDA is achieved, the Board shall award an additional
Bonus beyond the formula Bonus provided above, in an amount that it shall
determine in its sole discretion.

     (b)  Target EBITDA shall be established annually by the Board, or, at the
discretion of the Board, by the Compensation Committee and in either event, with
the concurrence of Executive as to the amount of Target EBITDA thereby
established. In the event of an acquisition, disposition or other similar
extraordinary corporate event which would significantly alter the Target EBITDA
established for that year, the parties shall negotiate in good faith to set new
levels of Target EBITDA.

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