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                                                                   EXHIBIT 99.3



                                November 1, 2000



Developers Diversified Realty Corporation
34555 Chagrin Boulevard
Moreland Hills, Ohio

         Re:      Voting Agreement

Ladies and Gentlemen:

                  The undersigned understands that Developers Diversified
Realty Corporation, an Ohio corporation ("DDRC"), DDR Transitory Sub Inc., a
Texas corporation ("DDR Sub"), and American Industrial Properties REIT, a Texas
real estate investment trust ("AIP"), are entering into an Agreement and Plan
of Merger to be dated on or about the date hereof (the "Agreement"), providing
for, among other things, the merger of DDR Sub into AIP (the "Merger").
Consummation of the Merger will require the approval of the shareholders of
AIP.

                  The undersigned is a shareholder of AIP (the "Shareholder")
and is entering into this letter agreement at your request, in exchange for
good and valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, to induce you to enter into the Agreement and to consummate the
transactions contemplated thereby.

                  The Shareholder confirms its agreement with you as follows:

                  1. The Shareholder represents and warrants that Schedule I
annexed hereto sets forth the shares of beneficial interest of AIP of which the
Shareholder or any affiliate (as defined under the Securities Exchange Act of
1934, as amended) of the Shareholder controlled by the Shareholder (a
"Controlled Affiliate") is the beneficial owner (the "Shares") and that the
Shareholder and the Controlled Affiliates are on the date hereof the lawful
owners of the number of Shares set forth in Schedule I, free and clear of all
liens, charges, encumbrances, voting agreements and commitments of any kind,
except as disclosed in Schedule I. Except for the Shares set forth in Schedule
I, neither the Shareholder nor any Controlled Affiliate owns or holds any
rights to acquire any additional shares of beneficial interest of AIP (other
than pursuant to options or conversion rights with regard to any of the Shares,
in each case as disclosed in Schedule I) or any interest therein or any voting
rights with respect to any such additional shares.

                  2. Until the earliest date referred to in Section 13, the
Shareholder agrees that it will not, and will not permit any Controlled
Affiliate to, contract to sell, sell or otherwise transfer or dispose of any of
the Shares or any interest therein or securities convertible into shares of
beneficial interest of AIP, or any voting rights with respect thereto, without
your prior written consent.

                  3. The Shareholder agrees that, during the term of this
letter agreement, neither it nor any Controlled Affiliate will take any action
that AIP would at that time be prohibited from taking under Section 4.1 of the
Agreement.

                  4. The Shareholder agrees that during the term of this letter
agreement (a) all of the shares of beneficial interest of AIP beneficially
owned by the Shareholder or any Controlled Affiliate, or




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over which the Shareholder or any Controlled Affiliate has voting power or
control, directly or indirectly (including any such shares acquired after the
date hereof) at the record date for any meeting of shareholders of AIP called
to consider and vote on the Merger and the Agreement and the transactions
contemplated thereby or any Acquisition Proposal (as such term is defined in
the Agreement) will be voted by the Shareholder or such Controlled Affiliates,
or any representative or proxy thereof, as applicable, in favor of the approval
of the Merger and the Agreement and the transactions contemplated thereby and
(b) neither the Shareholder nor any Controlled Affiliate, nor any such
representative or proxy, will vote any such shares in favor of any Acquisition
Proposal.

                  5. The Shareholder agrees that the shares referred to in
Section 4 above that are owned at the record date for any meeting of
shareholders of AIP called to consider and vote on the election of members of
the Board of Trust Managers of AIP (the "Board") will be voted by the
Shareholder or any Controlled Affiliate, or any representative or proxy
thereof, as applicable, in favor of the approval of the election of the
representatives of DDRC to the Board for so long as DDRC has the right to
nominate members of the Board under the Share Purchase Agreement dated July 30,
1998 between DDRC and AIP. This Section 5 will survive the termination of this
letter agreement until the earlier of (i) the Closing Date (as defined in the
Agreement) and (ii) the day on which the nomination right referred to above
first ceases to exist.

                  6. The Shareholder hereby appoints Marc A. Simpson to attend
the special meeting of the shareholders of AIP held to consider and vote on the
Merger and to vote the shares referred to in Section 4 above, with all the
power the Shareholder would possess if personally present, in favor of the
approval of the Merger, the Agreement and the transactions contemplated
thereby. The Shareholder agrees to execute, and to cause each Controlled
Affiliate to execute, such proxies and other instruments, and to take and to
cause each Controlled Affiliate to take, such actions as may be necessary to
cause all of those shares to be so voted.

                  7. The Shareholder hereby waives and releases and agrees not
to pursue, and will cause each Controlled Affiliate to waive and release and
agree not to pursue, any claim that the Shareholder or that Controlled
Affiliate now or hereafter has or may have against AIP or DDRC or any affiliate
of AIP or of DDRC, (i) arising out of or with respect to or in connection with
the Merger or the Agreement (including but not limited to any claim asserting
dissenters' rights), or any action taken or omitted to be taken by AIP, DDRC or
any such affiliate pursuant to or in connection with the Merger or the
Agreement and not in violation of the Agreement, or (ii) otherwise arising with
respect to or in connection with the Shareholder's or Controlled Affiliate's
(as applicable) interest in or rights with respect to shares of beneficial
interest of AIP, or AIP's or DDRC's or any of their respective affiliates'
actions in connection therewith on or prior to the date hereof. The Shareholder
further agrees that it will not accept or retain, and will not permit any
Controlled Affiliate to accept or retain, any payment, award or other benefit
of any kind arising out of or with respect to or in connection with any claim
or action initiated or asserted by any shareholder or class or other group of
shareholders of AIP (i) arising out of or with respect to or in connection with
the Merger or the Agreement (including but not limited to any claim asserting
dissenters' rights), or any action taken or omitted to be taken by AIP, DDRC or
any such affiliate pursuant to or in connection with the Merger or the
Agreement and not in violation of the Agreement, or (ii) otherwise arising out
of or with respect to or in connection with that shareholder's or class's or
group's (as applicable) status as a shareholder (or shareholders, as
applicable) of AIP, or AIP's or DDRC's or any of their respective affiliates'
actions in connection therewith on or prior to the date hereof.

                  Each of AIP and DDRC hereby waives and releases and agrees
not to pursue, and will cause each of its affiliates that it controls to waive
and release and agree not to pursue, any claim that it or that affiliate now or
hereafter has or may have with respect to or in connection with the
Shareholder's or



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any Controlled Affiliate's interest in or rights with respect to shares of
beneficial interest of AIP on or prior to the date hereof. Notwithstanding
anything to the contrary in this Section 7, the waiver, release and agreement
with respect to matters referred to in clause (ii) of each of the sentences of
the first paragraph of this Section 7, and the waiver, release and agreement
set forth in the first sentence of this paragraph, will not be effective unless
and until the Merger is consummated in accordance with the Agreement, and will
automatically become effective at the time of that consummation.

                  This Section 7 will survive the termination of this letter
agreement until the latest date permissible under applicable law.

                  8. The Shareholder has all necessary power and authority to
enter into this letter agreement and to give the waiver and release and enter
into the agreements set forth in Section 7 with respect to the Shares. This
letter agreement is the legal, valid and binding agreement of the Shareholder,
and is enforceable against the Shareholder in accordance with its terms,
subject to applicable bankruptcy, insolvency, fraudulent conveyance,
reorganization, moratorium and similar laws affecting creditors' rights and
remedies generally and to general principles of equity. This letter agreement
shall inure to the benefit of the parties hereto and the successors and assigns
of DDRC.

                  9. The Shareholder agrees that damages are an inadequate
remedy for the breach by Shareholder of any term or condition of this letter
agreement and that you shall be entitled to a temporary restraining order and
preliminary and permanent injunctive relief in order to enforce our agreements
herein.

                  10. Except to the extent that the laws of the jurisdiction of
organization of any party hereto, or any other jurisdiction, are mandatorily
applicable to matters arising under or in connection with this letter
agreement, this letter agreement shall be governed by the laws of the State of
Ohio. All actions and proceedings arising out of or relating to this letter
agreement shall be heard and determined in any United States District Court
sitting in the Northern District of Ohio.

                  11. Each of the parties hereto irrevocably submits to the
exclusive jurisdiction of any United States District Court located in the
Northern District of Ohio, for the purpose of any action or proceeding arising
out of or relating to this letter agreement and each of the parties hereto
irrevocably agrees that all claims in respect of such action or proceeding may
be heard and determined exclusively in any federal court sitting in the
Northern District of Ohio. Each of the parties hereto agrees that a final
judgment in any action or proceeding shall be conclusive and may be enforced in
other jurisdictions by suit on the judgment or in any other manner provided by
law.

                  The Shareholder hereby irrevocably appoints Jones, Day,
Reavis & Pogue, Cleveland, Ohio, as its lawful agent in and for the State of
Ohio, for and in its behalf, to accept and acknowledge service of, and upon
whom may be served, all necessary processes in any action, suit, or proceeding
arising under this Agreement that may be had or brought against it in any
federal court in the Northern District of Ohio, such service of process or
notice, or the acceptance thereof by said agent endorsed thereon, to have the
same force and effect as if served upon the Shareholder, provided that any such
process or notice that may be so served shall include a conspicuous statement
to the effect that is to be forwarded immediately to USAA Real Estate Company,
9830 Colonnade Boulevard, Suite 600, San Antonio, Texas 78230-2239, Attention:
Legal Counsel (with a copy to Patricia J. Villareal, Jones, Day, Reavis &
Pogue, 2001 Ross Avenue, Suite 2300, Dallas, Texas 75201). Nothing in this
Section 11 shall affect the right of any party hereto to serve legal process in
any other manner permitted by law. Shareholder hereby waives all defenses of
improper venue and forum non conveniens with respect to any action, suit, or
proceeding brought in the any United States District Court located in the
Northern District of Ohio and arising under this letter agreement.




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                  12. This letter agreement constitutes the entire agreement
between the parties hereto with respect to the matters covered hereby and
supersedes all prior agreements, understandings or representations between the
parties, written or oral, with respect to the subject matter hereof.

                  13. This letter agreement and the proxy granted pursuant to
Section 6 hereof shall become effective upon the execution and delivery of the
Agreement by the parties thereto. Except as otherwise provided herein, this
letter agreement and the proxy granted pursuant to Section 6 hereof shall
terminate automatically, without the need for any notice or other action by
either party, upon the earliest of (i) the date on which the Agreement is
terminated, (ii) the Closing Date, as defined in the Agreement, and (iii) May
31, 2001.

                  14. Each of the parties hereto intends that AIP be a third
party beneficiary of the provisions of this letter agreement of which it is not
a signatory, and is entitled to the benefits thereof and has the ability to
exercise the rights granted to DDRC herein as fully as if it were a full
signatory of this letter agreement.

                  15. Notwithstanding anything to the contrary contained
herein, neither AIP nor any representative of the Shareholder serving on the
Board of Trust Managers of AIP constitutes a Controlled Affiliate.



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                  Please confirm that the foregoing correctly states the
understanding between us by signing and returning to us a counterpart hereof.

                                                USAA Real Estate Company


                                                By: /s/ T. Patrick Duncan
                                                   ----------------------------
                                                Name:   T. Patrick Duncan
                                                Title:  Senior Vice President



Confirmed on the date
first above written

Developers Diversified Realty Corporation


By: /s/ James A. Schoff
    -----------------------------------------------
Name:  James A. Schoff
Title: Vice Chairman & Chief Investment Officer


Joining as a party with respect to Section 7 only:

American Industrial Properties REIT


By:  /s/ Charles W. Wolcott
    -----------------------------------------------
Name:  Charles W. Wolcott
Title: President & CEO




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                                   Schedule I

                   Ownership of Shares of Beneficial Interest


Owned Beneficially (including Options to Purchase Shares)



                                    Shares
                                   Owned of    Shares Subject
                                    Record        to Options      Total Shares
                                   ---------   --------------     ------------
                                                         
USAA Real Estate Company           1,685,346        -----          1,685,346








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