<PAGE>   1
                                                                   EXHIBIT 10.10


                                  July 30, 1998



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"), and American Industrial Properties
REIT, a Texas real estate investment trust ("AIP"), are entering into a Share
Purchase Agreement to be dated on or about the date hereof (the "Purchase
Agreement"), and, together with DDR Office Flex Corporation, a Delaware
corporation, a Merger Agreement to be dated on or about the date hereof (the
"Merger Agreement" and, together with the Purchase Agreement, the "Agreements"),
providing for, among other things, the purchase of common shares, $.10 par value
per share, of AIP by DDRC (the "Share Purchase"). Under the rules of the New
York Stock Exchange, consummation of the Share Purchase 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 Agreements 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 is the beneficial owner (the "Shares") and that the Shareholder is
on the date hereof the lawful owner 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, the Shareholder does not own or
hold 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. The Shareholder
represents and warrants that there are no affiliates of the Shareholder
controlled by the Shareholder. The Shareholder covenants that, in the event that
an affiliate of the Shareholder controlled by the Shareholder exists during the
term of this letter agreement, the Shareholder will cause such affiliate to act
in accordance with the terms of this letter agreement as if such affiliate were
the Shareholder. The Shareholder may, during the term of this letter agreement,
pledge the Shares, provided that each pledgee or transferee of such Shares has
agreed to be bound by the terms of this letter agreement. 


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Developers Diversified Realty Corporation
July 30, 1998
Page 2


        2. Until the earliest date referred to in Section 12, the Shareholder
agrees that it will not 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
it will not take any action that AIP would at that time be prohibited from
taking under Section 5.4 of the Purchase 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 over which the Shareholder 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 Share Purchase and the Agreements and the transactions contemplated
thereby or any Competing Transaction (as such term is defined in the Purchase
Agreement) will be voted by the Shareholder or any representative or proxy
thereof, as applicable, in favor of the approval of the Share Purchase and the
Agreements and the transactions contemplated thereby and (b) neither the
Shareholder nor any such representative or proxy will vote any such Shares in
favor of any Competing Transaction.

        5. The Shareholder agrees that the shares referred to in Section 4
above, 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
the Trust (the "Board"), will be voted by the Shareholder 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 the term of this letter
agreement.

        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 Share
Purchase 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 Share Purchase, the Agreements and the transactions contemplated
thereby. The Shareholder agrees to execute such proxies and other instruments as
may be necessary to cause all of those shares to be so voted.

        7. The Shareholder has all necessary power and authority to enter into
this letter agreement. 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.


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Developers Diversified Realty Corporation
July 30, 1998
Page 3


        8. 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.

        9. 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.

        10. 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.

        Shareholder hereby irrevocably appoints CSC/United States Corporation
Companies, 16 East Broad Street, Columbus, Ohio 43215, 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. Nothing in
this Section 10 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.

        11. 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.

        12. This letter agreement and the proxy granted pursuant to Section 6
hereof shall become effective upon the execution and delivery of the Agreements
by the respective 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 Purchase Agreement
and 


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Developers Diversified Realty Corporation
July 30, 1998
Page 4


the Merger Agreement are terminated, (ii) the Second Closing Date, as defined in
the Purchase Agreement, and (iii) the date that is 240 days after the date
hereof.

        13. Each of the parties hereto intends that AIP shall be a third party
beneficiary of this letter agreement, and shall be entitled to the benefits
hereof and shall have the ability to enforce the rights granted to DDRC herein
as fully as if it were a signatory of this letter agreement.



<PAGE>   5


Developers Diversified Realty Corporation
July 30, 1998
Page 5


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

                                Praedium II Industrial Associates LLC

                                By:  The Praedium Opportunity Fund II, L.P., its
                                     member


                                     By:  Praedium Advisors, Inc., its 
                                          managing general partner


                                          By: /s/ Christoper Hughes
                                             -----------------------------
                                          Name: Christopher Hughes
                                               ---------------------------
                                          Title: Vice President
                                                --------------------------

                                     By:  Praedium Partners, LLC, its 
                                          investment general partner

                                          By: /s/ Christopher Hughes
                                             -----------------------------
                                          Name: Christopher Hughes
                                               ---------------------------
                                          Title: Vice President
                                                --------------------------



Confirmed on the date
first above written

Developers Diversified Realty Corporation


By: /s/ Scott A. Wolstein
   ----------------------------------------
Name:Scott A. Wolstein
     --------------------------------------
Title: President
      -------------------------------------

<PAGE>   6
                                   Schedule I

                   Ownership of Shares of Beneficial Interest


<TABLE>
<CAPTION>
Owned Beneficially (including Options to Purchase Shares)
---------------------------------------------------------
<S>                                   <C>
Options                                   None

Trust Common Shares                    733,945
</TABLE>