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                                                                  Exhibit 10.18


                              [COMPANY LETTERHEAD]


        ADDENDUM TO ORIGINAL EMPLOYMENT LETTER DATED SEPTEMBER 19, 1997:

February 28, 1997

Mr. Robert LaMere
207 Wedgewood Circle
Carl Junction, Missouri 64834

Dear Bob:

It is my pleasure to offer you a position with HighwayMaster Corporation as the
Senior Vice President of Transportation Systems, with your employment date to
be Saturday, March 1, 1997. You will be reporting to Gordon Quick, the Chief
Operating Officer. Your initial job responsibilities have been outlined for you
and you will receive them from your direct report.

The monthly salary for this exempt position is ten thousand four hundred
sixteen dollars and sixty-seven cents ($10,416.67). The position is terminable
at will, by either party, and HighwayMaster Corporation may change your salary
or job responsibilities from time to time as it deems necessary. If the change
results in a reduction in either your salary or job responsibilities, you may
elect to terminate your employment and receive your six (6) months severance.
Medical, dental, life, short and long term disability will be provided for you
at the Company's expense, although HighwayMaster Corporation reserves the right
to change carriers or coverage levels. Medical and dental insurance will be
available at group rates for your dependents at your expense. Coverage for you
will be the first of the month following thirty (30) days of employment. Your
initial vacation eligibility will be three (3) weeks per year earned at ten
(10) hours per month. Additional benefits include six (6) paid sick days per
year, the Company paid holidays and 401(k) plan.

We will issue a check for seventy thousand dollars ($70,000), which you can
utilize for all of your relocation expenses after we receive written
confirmation of your employment letter. You must remain in the company's
employment for one (1) year from your relocation date, (this is valid if you
decide to leave the company and null and void, if the company terminates your
employment) or you will have to reimburse the company for all of your
relocation expenses.



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Mr. Robert LaMere
February 28, 1997
Page Two

You will receive thirty thousand (30,000) stock options and the price will be
determined on your employment date with the company, March 1, 1997.
Additionally, if termination should occur, you will be entitled to six (6)
months severance, paid in lump sum based on your base salary and this will be
applicable for the first three (3) years of your employment.

You will be eligible to receive a fifteen thousand dollar ($15,000) bonus upon
the closing of the Burlington Motors/HighwayMaster Corporation software
agreement.

You will receive periodical performance review, at which time we will evaluate
your performance, position and compensation with no guarantee of change at that
time.

I believe that you will find the position challenging and commensurate with
your talents and objectives. We look forward to you becoming a part of our
team.

Please sign, date and return the duplicate copy of this letter to confirm that
it clearly states our mutual understanding and your acceptance of the position.

In order to expedite the orientation process, I would appreciate it, if you
would bring your driver's license and social security card/birth certificate
with you on your first da.

If you have any questions or concerns regarding this matter, please contact me
at (972)-732-2506.

Sincerely                              Accepted by

CAROLYN LOCKE

Carolyn Locke                          /s/ ROBERT LAMERE
Director of Human Resources            ------------------------------------
                                       Robert LaMere

                                       Date: 3/4/97
                                            -------------------------------
cc:  Gordon Quick
     Personnel File