OFFER TO PURCHASE
               ALL OUTSTANDING CLASS A AND CLASS B COMMON SHARES
                                      OF
                      SIMON TRANSPORTATION SERVICES INC.
                                      AT
                           $7.00 NET CASH PER SHARE
                                      BY
                                  JERRY MOYES


  THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 5:00 P.M., EASTERN TIME, ON
                 JUNE 21, 2000, UNLESS THE OFFER IS EXTENDED.


                                                                   May 23, 2000

To Our Clients:

   Enclosed for your consideration are the offer to purchase, dated May 23,
2000 (the "Offer to Purchase"), and the related Letter of Transmittal (which,
as amended or supplemented from time-to-time, together constitute the "Offer")
in connection with the Offer by Jerry Moyes (the "Purchaser") to purchase all
outstanding shares of Class A Common Stock, $.01 par value (the "Class A
Common Shares") and Class B Common Stock, $.01 par value (the "Class B Common
Shares" and, together with the Class A Common Shares, the "Shares"), of Simon
Transportation Services Inc., a Nevada corporation (the "Company"), at a price
of $7.00 per Share, net to the seller in cash, without interest thereon, upon
the terms and subject to the conditions set forth in the Offer to Purchase.

   Stockholders whose certificates evidencing Shares (the "Share
Certificates") are not immediately available or who cannot deliver their Share
Certificates and all other documents required by the Letter of Transmittal to
the Depositary prior to the Expiration Date (as defined in the Offer to
Purchase) or who cannot complete the procedure for delivery by book-entry
transfer to the Depositary's account at the Book-Entry Transfer Facility (as
defined in Section 2 of the Offer to Purchase) on a timely basis and who wish
to tender their Shares must do so pursuant to the guaranteed delivery
procedure described in Section 2 of the Offer to Purchase (see also
Instruction 2 of the Letter of Transmittal). Delivery of documents to the
Book-Entry Transfer Facility in accordance with the Book-Entry Transfer
Facility's procedures does not constitute delivery to the Depositary.

   THIS MATERIAL IS BEING SENT TO YOU AS THE BENEFICIAL OWNER OF SHARES HELD
BY US FOR YOUR ACCOUNT BUT NOT REGISTERED IN YOUR NAME. WE ARE THE HOLDER OF
RECORD OF SHARES HELD BY US FOR YOUR ACCOUNT. A TENDER OF SUCH SHARES CAN BE
MADE ONLY BY US AS THE HOLDER OF RECORD AND PURSUANT TO YOUR INSTRUCTIONS. THE
LETTER OF TRANSMITTAL IS BEING FURNISHED TO YOU FOR YOUR INFORMATION ONLY AND
CANNOT BE USED BY YOU TO TENDER SHARES HELD BY US FOR YOUR ACCOUNT.

   We request instructions as to whether you wish to have us tender on your
behalf any or all of the Shares held by us for your account upon the terms and
subject to the conditions set forth in the Offer to Purchase.

   Your attention is invited to the following:

     1. The tender price is $7.00 per Share, net to you in cash, without
  interest thereon.

     2. The Offer and withdrawal rights will expire at 5:00 P.M., Eastern
  time, on June 21, 2000, unless the Offer is extended.

     3. The Offer is being made for all of the outstanding Shares.

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   Tendering stockholders will not be obligated to pay brokerage fees or
commissions or, except as set forth in Instruction 6 of the Letter of
Transmittal, stock transfer taxes on the purchase of Shares by the Purchaser
pursuant to the Offer.

   The Offer is made solely by the Offer to Purchase and the related Letter of
Transmittal and any supplements or amendments thereto and is being made to all
holders of Shares. The Offer is not being made to (nor will tenders be
accepted from or on behalf of) holders of Shares in any jurisdiction in which
the making of the Offer or the acceptance thereof would not be in compliance
with the securities, blue sky, or other laws of such jurisdiction. The
Purchaser is not aware of any jurisdiction in which the making of the Offer or
the acceptance thereof would not be in compliance with the laws of such
jurisdiction. In any jurisdiction the securities, blue sky, or other laws of
which require the Offer to be made by a licensed broker or dealer, the Offer
is being made on behalf of the Purchaser by one or more registered brokers or
dealers licensed under the laws of such jurisdiction.

   If you wish to have us tender any or all of your Shares, please so instruct
us by completing, executing, and returning to us the instruction form
contained in this letter. An envelope in which to return your instructions to
us is enclosed. If you authorize the tender of your Shares, all such Shares
will be tendered unless otherwise specified on the instruction form contained
in this letter. Your instructions should be forwarded to us in ample time to
permit us to submit a tender on your behalf prior to the expiration of the
Offer.

   If holders of Shares wish to tender Shares, but it is impracticable for
them to forward their Share Certificates or other required documents to the
Depositary prior to the Expiration Date or to comply with the procedures for
book-entry transfer on a timely basis, a tender may be effected by following
the guaranteed delivery procedures specified under Section 2 of the Offer to
Purchase.

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              INSTRUCTIONS WITH RESPECT TO THE OFFER TO PURCHASE

               ALL OUTSTANDING CLASS A AND CLASS B COMMON SHARES
                                      OF
                      SIMON TRANSPORTATION SERVICES INC.
                                      AT
                           $7.00 NET CASH PER SHARE
                                      BY
                                  JERRY MOYES

   The undersigned acknowledge(s) receipt of your letter and the enclosed
offer to purchase, dated May 23, 2000 (the "Offer to Purchase"), and the
related Letter of Transmittal (which, as amended or supplemented from time-to-
time, together constitute the "Offer"), in connection with the Offer by Jerry
Moyes (the "Purchaser") to purchase all outstanding Shares at $7.00 per Share,
net to the seller in cash without interest thereon, upon the terms and subject
to the conditions set forth in the Offer to Purchase.

   This will instruct you to tender to the Purchaser the number of Shares
indicated below (or, if no number is indicated below, all Shares) held by you
for the account of the undersigned, upon the terms and subject to the
conditions set forth in the Offer.

Number and Type (Class A Common Shares and/or Class B Common Shares) of Shares
to be Tendered*:
_______________________________________________________________________________
Account Number: _______________________________________________________________
Signature(s): _________________________________________________________________
_______________________________________________________________________________
Dated: _______________ , 2000
Please type or print name(s): _________________________________________________
_______________________________________________________________________________
Please type or print address(es) here: ________________________________________
_______________________________________________________________________________
Area Code and Telephone Number: _______________________________________________
Taxpayer Identification or Social Security Number(s): _________________________

- --------
*  Unless otherwise indicated, it will be assumed that all Shares held by us
   for your account are to be tendered and that all Shares are Class A Common
   Shares.

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