<PAGE>
 
                                                                     EXHIBIT 3.3

                     RESTATED CERTIFICATE OF INCORPORATION
                                       OF
                      UNITED RENTALS (NORTH AMERICA), INC.



          United Rentals (North America), Inc., a corporation organized and
existing under the laws of the State of Delaware (the "Corporation"), hereby
certifies as follows:

          1.  The name of the corporation is United Rentals (North America),
Inc.  The original certificate of incorporation of the Corporation was filed
with the Secretary of State of the State of Delaware on August 14, 1997, under
the name United System, Inc.

          2.  Pursuant to Section 245 of the Delaware General Corporation Law,
this Restated Certificate of Incorporation only restates and integrates, and
does not further amend, the provisions of the Corporation's certificate of
incorporation as heretofore amended or supplemented (the "Certificate of
Incorporation"), there being no discrepancy between those provisions and the
provisions of this Restated Certificate of Incorporation.

          3.  The terms and provisions of this Restated Certificate of
Incorporation have been duly adopted pursuant to the provisions of Section 245
of the Delaware General Corporation Law.

          4.  The text of the Certificate of Incorporation is hereby restated to
read in its entirety as follows:


                                   ARTICLE I.

          The name of the Corporation is United Rentals (North America), Inc.

                                  ARTICLE II.

          The address of the Corporation's registered office in the State of
Delaware is United Corporate Services, Inc., 15 East 
<PAGE>
 
North Street, Dover, Delaware 19901, County of Kent. The name of its registered
agent at such address is United Corporate Services, Inc.

                                  ARTICLE III.

          The aggregate number of shares which the Corporation shall have
authority to issue shall be three thousand (3,000), consisting of three thousand
(3,000) shares of Common Stock, par value $0.01 per share.

                                  ARTICLE IV.

          The purpose of the Corporation is to engage in any lawful act or
activity for which corporations may now or hereafter be organized under the
Delaware General Corporation Law.

                                   ARTICLE V.

          A.   By-Laws.  In furtherance and not in limitation of the powers
               -------                                                     
conferred by statute, the Board of Directors is expressly authorized to make,
adopt, alter, amend or repeal the By-Laws of the Corporation.  Any By-Laws made
by the directors under the powers conferred hereby may be amended or repealed by
the directors or by the stockholders.  Notwithstanding the foregoing and
anything contained in this Restated Certificate of Incorporation to the
contrary, the By-Laws shall not be amended or repealed by the stockholders, and
no provision inconsistent therewith shall be adopted by the stockholders,
without the affirmative vote of the holders of at least 66-2/3% of the voting
power of all shares of the Corporation entitled to vote generally in the
election of directors, voting together as a single class.

          B.   Amendment of Certificate of Incorporation. Notwithstanding any
               -----------------------------------------                     
other provision contained in this Restated Certificate of Incorporation and
notwithstanding that a lesser percentage may be specified by law, the By-Laws or
otherwise, this Article V and Articles VI, VII, VIII and IX of this Restated
Certificate of Incorporation shall not be amended or repealed, and no provision
inconsistent therewith or providing for cumulative voting in the election of
directors shall be adopted, unless such adoption, amendment or repeal is
approved by the affirmative vote of holders of at least 66-2/3% of the voting

                                       2
<PAGE>
 
power of all shares of capital stock of the Corporation entitled to vote
generally for the election of directors.

                                  ARTICLE VI.

          The business and affairs of the Corporation shall be managed by and
under the direction of the Board of Directors (the "Board").  The Board may
exercise all such authority and powers of the Corporation and do all such lawful
acts and things as are not by statute or this Restated Certificate of
Incorporation directed or required to be exercised or done by the stockholders.

          A.   Number of Directors.  The number of directors comprising the
               -------------------                                         
entire Board shall, subject to the right, if any, of holders of Preferred Stock
to elect directors under specified circumstances, be such number as may be fixed
from time to time exclusively by the Board by action of a majority of the
directors then in office.  If the number of directors at any time is fixed at
three or greater, then thereafter in no event shall such number be fewer than
three or greater than nine, unless approved by action of not less than two-
thirds of the directors then in office.  No director need be a stockholder.

          B.   Classes and Terms of Directors.  The directors shall be divided
               ------------------------------                                 
into three classes (I, II and III).  The number of directors comprising each
class (assuming no vacancy in any class) shall be as nearly equal in number as
possible based upon the number of directors comprising the entire Board.  The
Board shall, at or before the first meeting of the Board following the Effective
Time (as that term is defined in the document titled "Amended and Restated
Certificate of Incorporation of United System, Inc." filed with the Delaware
Secretary of State on September 11, 1997), designate the class to which each
director then serving shall be a member.  The initial term of the directors in
Class I shall extend until the first annual meeting of stockholders following
the Effective Time; the initial term of the directors in Class II shall extend
until the second annual meeting of stockholders following the Effective Time;
and the initial term of the directors in Class III shall extend until the third
annual meeting of stockholders following the Effective Time.  At each annual
meeting of stockholders, successors to directors of the class whose term expires
at such meeting will be elected to serve for three-year terms and until their
successors are elected and qualified.

                                       3
<PAGE>
 
          C.   Newly-Created Directorships and Vacancies. Subject to the rights
               -----------------------------------------                       
of the holders of any class or series of Preferred Stock then outstanding, newly
created directorships resulting from any increase in the number of directors or
any vacancies in the Board resulting from death, resignation, retirement,
disqualification, removal from office or any other cause may be filled by the
Board (and not by the stockholders unless there are no directors then in
office), provided that a quorum is then in office and present, or by a majority
of the directors then in office, if less than a quorum is then in office, or by
the sole remaining director.  A director elected to fill a newly created
directorship or other vacancy shall hold office for the remainder of the full
term of the class of directors in which the new directorship was created or the
vacancy occurred and until such director's successor has been elected and
qualified.

          D.   Removal of Directors.  Subject to the rights of the holders of
               --------------------                                          
any class or series of Preferred Stock then outstanding, the directors or any
director may be removed from office any time, but only for cause, at a meeting
called for that purpose, and only by the affirmative vote of the holders of at
least 66-2/3% of the voting power of all shares of the Corporation entitled to
vote generally in the election of directors, voting together as a single class.

          E.   Rights of Holders of Preferred Stock.  Notwithstanding the
               ------------------------------------                      
foregoing provisions of this Article VI, whenever the holders of any one or more
classes or series of Preferred Stock issued by the Corporation shall have the
right, voting separately by class or series, to elect directors at an annual or
special meeting of stockholders, the election, term of office, filling of
vacancies and other features of such directorships shall be governed by the
rights and preferences of such Preferred Stock, and such directors so elected
shall not be divided into classes pursuant to this Article VI unless expressly
provided by such rights and preferences.

          F.   Written Ballot Not Required.  The election of directors need not
               ---------------------------                                     
be by written ballot unless the By-Laws of the Corporation shall so provide.

                                       4
<PAGE>
 
                                  ARTICLE VII.

          The By-Laws of the Corporation may provide, without limitation,
requirements relating to the notice and conduct of annual meetings, special
meetings, and the nomination and election of directors of the Corporation.

                                 ARTICLE VIII.

          In furtherance and not in limitation of the powers conferred by law or
in this Restated Certificate of Incorporation, the Board (and any committee of
the Board) is expressly authorized, to the extent permitted by law, to take such
action or actions as the Board or such committee may determine to be reasonably
necessary or desirable to (a) encourage any person to enter into negotiations
with the Board and management of the Corporation with respect to any transaction
which may result in a change in control of the Corporation which is proposed or
initiated by such person or (b) contest or oppose any such transaction which the
Board or such committee determines to be unfair, abusive or otherwise
undesirable with respect to the Corporation and its business, assets or
properties or the stockholders of the Corporation, including, without
limitation, the adoption of plans or the issuance of rights, options, capital
stock, notes, debentures or other evidences of indebtedness or other securities
of the Corporation, which rights, options, capital stock, notes, evidences of
indebtedness and other securities (i) may be exchangeable for or convertible
into cash or other securities on such terms and conditions as may be determined
by the Board or such committee and (ii) may provide that any holder or class of
holders thereof designated by the Board or any such committee will be treated
differently than all other holders in respect of the terms, conditions,
provisions and rights of such securities.

                                  ARTICLE IX.

          Subject to the rights, if any, of holders of any class or series of
Preferred Stock then outstanding, (i) stockholders are not permitted to call a
special meeting of stockholders or to require the Board or officers of the
Corporation to call such a special meeting, (ii) a special meeting of
stockholders may only be called by a majority of the Board or by the chief
executive officer, (iii) the business permitted to be conducted at a 

                                       5
<PAGE>
 
special meeting of stockholders shall be limited to matters properly brought
before the meeting by or at the direction of the Board, and (iv) any action
required or permitted to be taken by the stockholders must be taken at a duly
called and convened annual meeting or special meeting of stockholders and cannot
be taken by consent in writing.

          Meetings of stockholders may be held within or without the State of
Delaware, as the By-Laws may provide.  The books of the Corporation may be kept
(subject to any provision contained in the statute) outside the State of
Delaware at such place or places as may be designated from time to time by the
Board or in the By-Laws of the Corporation.

                                   ARTICLE X.

          A director of the Corporation shall not be personally liable to the
Corporation or its stockholders for monetary damages for any breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the Delaware General Corporation
Law, or (iv) for any transaction from which the director derived an improper
personal benefit.  If the Delaware General Corporation Law is amended after
approval by the stockholders of this Article to authorize corporate action
further eliminating or limiting the personal liability of directors, then the
liability of a director shall be eliminated or limited to the fullest extent
permitted by the Delaware General Corporation Law, as so amended.

                                  ARTICLE XI.

          Any act or transaction by or involving the Corporation that requires
for its adoption under the General Corporation Law of the State of Delaware or
this certificate of incorporation the approval of the stockholders of the
Corporation shall, by virtue of this reference to Section 251(g) of the General
Corporation Law of the State of Delaware, require, in addition, the approval of
the stockholders of United Rentals, Inc., a Delaware corporation, or any
successor thereto by merger, by the same vote that is required by the General
Corporation Law of the State of 

                                       6
<PAGE>
 
Delaware and/or the certificate of incorporation of this Corporation.

          IN WITNESS WHEREOF, the Corporation has caused this Restated
Certificate of Incorporation to be duly executed this 12th day of August, 1998.


                         United Rentals (North America), Inc.


                         By:/s/ Sandra E. Welwood
                            ---------------------
                            Name: Sandra E. Welwood
                            Title: Vice President

                                       7