Exhibit 99.1


                         RICHARD D. COLBURN and AYR INC.

                                 1120 La Colina
                         Beverly Hills, California 90210



                                                        March 17, 2002

United Rentals, Inc.
Five Greenwich Office Park
Greenwich CT 06830

Gentlemen:

1.   Sale

     (a)  Ayr Inc, a California corporation wholly-owned by Mr. Richard Colburn
          ("Ayr"), hereby sells to United Rentals, Inc. (the "Company"), and the
          Company hereby purchases from Ayr, 50,882 shares (the "Colburn Sold
          Shares") of Common Stock of the Company ("Common Stock") at $29.48 per
          share, for an aggregate purchase price of $1,500,000 (the "Colburn
          Purchase Price"). Mr. Colburn will as soon as practicable in the
          circumstances cause Ayr to deliver to the Company a certificate for
          the Colburn Sold Shares, together with a stock power therefor endorsed
          in blank, and the Company will pay the Colburn Purchase Price to Ayr
          against receipt of the stock certificate and stock power. Ayr may
          deliver to the Transfer Agent a certificate representing more than the
          Colburn Sold Shares, in which case the Company will, and will cause
          Transfer Agent to, take such action as may be necessary to transfer to
          the Company or to cancel the Colburn Sold Shares, and to return one or
          more certificates in such forms and amounts as Mr. Colburn may request
          for all shares in excess of the Colburn Sold Shares; such action shall
          be deemed delivery to the Company so long as Mr. Colburn and Ayr take
          any action and executes any documents reasonably requested by the
          Company or the Transfer Agent in connection therewith, and the Company
          will promptly wire transfer to Ayr or its order the amount of the
          Colburn Purchase Price.

     (b)  Mr. Colburn and Ayr represent that Ayr owns the Colburn Sold Shares
          free and clear of all liens, claims and encumbrances and that, upon
          delivery of the Colburn Sold Shares as provided above, Mr. Colburn and
          Ayr will have delivered title to the Colburn Sold Shares to the
          Company free and clear of all liens, claims and encumbrances. Mr.
          Colburn and Ayr make no other representations or warranties whatsoever
          with respect to the Sold Shares. Neither the Company nor any of its
          affiliates makes any representations or warranties whatsoever to Mr.
          Colburn or Ayr. Mr. Colburn and Ayr are entering into this transaction
          solely as a result of such investigations as they deemed appropriate.
          The Company has made an independent



          decision to purchase the Colburn Sold Shares, free of any influence by
          Mr. Colburn or Ayr.

2.   In order to induce the Company to purchase the Colburn Sold Shares, Mr.
     Colburn and Ayr (together, the "Covenantors") jointly and severally agree
     that, during the 180-day period beginning on the date hereof, neither of
     the Covenantors will, nor will any of their affiliates on their behalf,
     without the prior written consent of the Company, make any contractual or
     other demand to register any shares of Common Stock in a manner that would
     require the filing of a registration statement before the end of such
     180-day period, or offer, sell, contract to sell, or otherwise dispose of,
     any shares of Common Stock or any other securities of the Company or any
     derivative securities or derivative contracts the value of which is
     determined in whole or in substantial part (with substantial to mean more
     than 5%) by reference to the value of securities of the Company, whether or
     not such Common Stock or other securities have been registered and whether
     or not such offer, sale, contract or other disposition could otherwise be
     made under Rule 144 or otherwise.

3.   The Covenantors release the Company and its affiliates from any claim that,
     and the Covenantors will not complain if, the Company and its affiliates
     possessed relevant information which the Covenantors did not possess, or
     which the Company or any affiliate should have disclosed publicly or to the
     Covenantors or any of them. Similarly, the Covenantors will not complain if
     for whatever reason the price of the Company's securities hereafter
     increases for any reason whatsoever, or if the Company or any of its
     affiliates at any time or times hereafter sells any Company securities at
     any price.

4.   This Agreement may not be changed or terminated orally. It sets forth all
     understandings of the parties with respect to the subject matter hereof. It
     shall be governed by the internal laws of the State of Connecticut. The
     federal and state courts in Fairfield County Connecticut shall have
     exclusive jurisdiction on all matters relating to this Agreement.

5.   This agreement shall become a binding contract only if it or a counterpart
     copy of it is signed by each party, with facsimile copies transmitted to
     the agents of the other parties, by 12:00 Midnight, Pacific Time, March 17,
     2002.

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UNITED RENTALS, INC.                             AYR, INC.





By                                               BY
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                                                 ------------------------------

                                                 Richard Colburn

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