<PAGE>
Exhibit 10.18

                                                                  EXECUTION COPY

                 NINTH AMENDMENT, WAIVER AND OVERRIDE AGREEMENT

         NINTH AMENDMENT, WAIVER AND OVERRIDE AGREEMENT, dated as of June 6,
2002 (this "Amendment"), to the Credit Agreement, dated as of August 11, 1999
(as amended, supplemented or otherwise modified prior to the date hereof, the
"Existing Credit Agreement," as modified hereby and as further amended,
supplemented or otherwise modified from time to time, the "Credit Agreement"),
among CELADON GROUP, INC., a Delaware corporation ("Group") and CELADON TRUCKING
SERVICES, INC., a New Jersey corporation ("Trucking," together with Group, each
a "Borrower," collectively, the "Borrowers") the banks and other financial
institutions parties thereto (the "Lenders"), and ING CAPITAL LLC (formerly
known as ING (U.S.) CAPITAL LLC), as administrative agent (the "Administrative
Agent") and arranger for the Lenders.

                                    RECITALS

         The Borrowers have requested that the Administrative Agent and the
Lenders agree to amend, waive and override certain provisions of the Credit
Agreement as set forth in this Amendment. The Administrative Agent and the
Lenders parties hereto are willing to agree to such amendments, waivers and
override provisions, but only on the terms and subject to the conditions set
forth in this Amendment.

         NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the Borrowers, the Administrative Agent and the Lenders hereby
agree as follows:

     1. Defined Terms. Unless otherwise defined herein, terms defined in the
Credit Agreement are used herein as therein defined.

     2. Amendments.

               (a) Subsection 8.2(d) of the Existing Credit Agreement is hereby
          amended by deleting such subsection in its entirety and substituting
          in lieu thereof the following new subsection (d), to read in its
          entirety as follows:

                    "(d) within three (3) Business Days following the last
                    Business Day of every other week, a Borrowing Base
                    Certificate showing the Borrowing Base as of the last
                    Business Day of such two week period, certified as complete
                    and correct by a Responsible Officer;"

               (b) Subsections 9.1 (d) and (e) of the Existing Credit Agreement
          are hereby amended by deleting such subsections in their entirety and
          substituting in lieu thereof the following new subsections (d) and
          (e), to read in their entirety as follows:

                    "(d) Limitation on Leasing. Permit, at any time during any
                    period set forth below, the sum of (i) all Financing Leases,
                    and (ii) all obligations of each Borrower or any of its
                    Subsidiaries in respect of any lease of real or personal
                    property, including, without limitation, residual payments
                    required pursuant to terminal rental adjustment clauses set
                    forth in leases of tractors and trailers the term of which
                    is more than one year from such time, in respect of which
                    the Borrower or any of its Subsidiaries is


<PAGE>

                    obligated as lessee or a user, which lease obligations shall
                    be discounted at a rate equal to the rate set forth in such
                    lease, to exceed the amount set forth opposite such period
                    below:
<Table>
<Caption>

                    ----------------------------------------------------------------- ---------------------
                                              Test Period                                    Amount
                    ----------------------------------------------------------------- ---------------------
                    <S>                          <C>      <C>                         <C>
                    September 30, 2001           to       December 31, 2002           $142,000,000
                    ---------------------------- -------- --------------------------- ---------------------
                    January 1, 2003              to       June 30, 2003               $144,000,000
                    ---------------------------- -------- --------------------------- ---------------------
</Table>
                    (e) Minimum EBITDA. Permit Consolidated EBITDA for any
                    fiscal quarter set forth below to be less than the amount
                    set forth opposite such fiscal quarter in the column headed
                    "Fiscal Quarter Amount" below; provided, however, in the
                    event that the Consolidated EBITDA for such fiscal quarter
                    is less than the amount set forth opposite such fiscal
                    quarter in the column headed "Fiscal Quarter Amount" below,
                    the Borrowers shall nonetheless be in compliance with this
                    subsection if (1) in the case of the fiscal quarters ending
                    March 31, 2002, June 30, 2002, September 30, 2002 and
                    December 31, 2002, respectively, the Cumulative Consolidated
                    EBITDA for such fiscal quarter exceeds the amount set forth
                    opposite such fiscal quarter in the column headed
                    "Cumulative Amount" below (for purposes of this subsection,
                    "Cumulative Consolidated EBITDA" shall mean the aggregate
                    amount of Consolidated EBITDA for a period beginning with
                    the fiscal quarter ending December 31, 2001 and ending at
                    the end of the relevant fiscal quarter), or (ii) in the case
                    of the fiscal quarters ending March 31, 2003 and June 30,
                    2003, respectively, the aggregate amount of Consolidated
                    EBITDA for the four consecutive fiscal quarters ending on
                    March 31, 2003 and June 30, 2003, respectively, exceeds the
                    amount set forth opposite such fiscal quarter in the column
                    headed "Cumulative Amount" below:
<Table>
<Caption>
                    --------------------------------- ----------------------- ----------------------
                         Fiscal Quarter Ending        Fiscal Quarter Amount     Cumulative Amount
                    --------------------------------- ----------------------- ----------------------
                    <S>                               <C>                     <C>
                    December 31, 2001                 $4,650,000              $4,650,000
                    --------------------------------- ----------------------- ----------------------
                    March 31, 2002                    $4,750,000              $9,400,000
                    --------------------------------- ----------------------- ----------------------
                    June 30, 2002                     $5,000,000              $14,400,000
                    --------------------------------- ----------------------- ----------------------
                    September 30, 2002                $5,300,000              $19,700,000
                    --------------------------------- ----------------------- ----------------------
                    December 31, 2002                 $5,300,000              $25,000,000
                    --------------------------------- ----------------------- ----------------------
                    March 31, 2003                    $5,500,000              $22,000,000
                    --------------------------------- ----------------------- ----------------------
                    June 30, 2003                     $5,700,000              $23,000,000"
                    --------------------------------- ----------------------- ----------------------
</Table>
     3. Waivers.

               (a) Each of the Administrative Agent and the Lenders hereby waive
          any Default or Events of Default resulting from the Borrowers' failure
          to comply with (i) Section 5.5(c) (Mandatory Prepayments), (ii)
          Section 9.2 (Limitation on Indebtedness), (iii) Section 9.3
          (Limitation on Liens), and (iv) Section 9.6(a) (Limitation on Sale of
          Assets) of the Existing Credit Agreement as a result of the execution
          and delivery of the Purchase and Sale Agreement, dated March 18, 2002
          (as in effect on the date hereof and as such Purchase and Sale
          Agreement may be modified, amended or supplemented with the consent of
          the Administrative Agent, the "Sale Agreement"), between Trucking, as
          buyer, and Foothill Capital Corporation, as seller, and any other
          documents




                                      -58-
<PAGE>

          executed and delivered in connection therewith (such documents,
          together with the Sale Agreement, the "Sale Documents"), and the
          performance by Trucking of its obligations under the Sale Documents in
          accordance with the terms thereof; provided, that such waiver is
          granted upon the following conditions: (A) the Sales Documents are not
          modified, amended or supplemented without the consent of the
          Administrative Agent, (B) the Borrowers have delivered to the
          Administrative Agent a true and complete copy of all the Sale
          Documents, and (C) the Borrowers have satisfied all the requirements
          set forth in Section 8.11 (Additional Collateral; Additional
          Guarantors) of the Existing Credit Agreement. It is further agreed
          that if the Borrowers fail to satisfy any of the conditions set forth
          herein, such waiver shall fail to be in effect.

               (b) Each of the Administrative Agent and the Lenders hereby waive
          any Default or Events of Default resulting from the Borrowers' failure
          to comply with (1) Section 5.5(c) (Mandatory Prepayments), and (ii)
          Section 9.6(a) (Limitation on Sale of Assets) of the Existing Credit
          Agreement as a result of the execution and delivery of the Auction
          Agreement, dated March 18, 2002 (as in effect on the date hereof and
          as such Auction Agreement may be modified, amended or supplemented
          with the consent of the Administrative Agent, the "Auction
          Agreement"), between Trucking, as seller, and Taylor & Martin, Inc. --
          Auctioneers, as auctioneers, and the performance by Trucking of its
          obligations under the Auction Agreement in accordance with the terms
          thereof; provided, that such waiver is granted upon the following
          conditions: (A) the Auction Agreement is not modified, amended or
          supplemented without the consent of the Administrative Agent, (B) the
          Borrowers have delivered to the Administrative Agent a true and
          complete copy of the Auction Agreement and any other documents
          executed and delivered in connection therewith, and (C) the Borrowers
          have satisfied all the requirements set forth in Section 8.11
          (Additional Collateral; Additional Guarantors) of the Existing Credit
          Agreement. It is further agreed that if the Borrowers fail to satisfy
          any of the conditions set forth herein, such waiver shall fail to be
          in effect.

     4. Override Provisions. Notwithstanding the provisions of Sections 9.6(a)
and 5.5(c) of the Existing Credit Agreement, in the event Trucking enters into
an agreement with Transport International Pool ("TIP") for the sale by Trucking
to TIP of 300 trailers and other equipment thereto (as more accurately described
in the Celadon Proposal -- Trade Group 5, dated February 27, 2002 (as in effect
on the date hereof and as such TIP Proposal may be modified, amended or
supplemented with the consent of the Administrative Agent, the "TIP Proposal"),
50% of the Net Proceeds of such sale (regardless if such sale is a single
payment or a series of payments) shall be applied first to installments of
principal of the Term Loans until paid in full, and second to the reduction of
the Revolving Credit Commitments and the prepayment of the Revolving Credit
Loans and/or to cash collateralize or replace Letters of Credit. Prepayments of
installments of Term Loans shall be applied in the inverse order of maturity and
such amounts so prepaid may not be reborrowed. Such override provisions provided
for herein are granted on the following conditions: (A) the TIP Proposal is not
modified, amended or supplemented without the consent of the Administrative
Agent, (B) the Borrowers have delivered to the Administrative Agent a true and
complete copy of the TIP Proposal and any other documents executed and delivered
in connection therewith, and (C) the Borrowers have satisfied all the
requirements set forth in Section 8.11 (Additional Collateral; Additional
Guarantors) of the Existing Credit Agreement. It is further agreed that if the
Borrowers fail to satisfy any of the conditions set forth herein, such override
provisions shall fail to be in effect.

     5. Condition Precedent. This Amendment shall become effective on the date
(the "Amendment Effective Date") on which the following conditions precedent
shall have been satisfied:

               (a) receipt by the Administrative Agent of this Amendment,
          executed and delivered by duly authorized officers of the Lenders and
          the Borrowers and acknowledged by each of the Guarantors; and



                                      -59-
<PAGE>
               (b) receipt by the Administrative Agent of any other documents
          relating hereto that shall be reasonably requested by the
          Administrative Agent.

     6. No Default. On the Amendment Effective Date, (i) the Borrowers shall be
in compliance with all the terms and provisions set forth in the Loan Documents
on its part to be observed or performed, (ii) the representations and warranties
made and restated by each Borrower pursuant to Section 7 of this Amendment shall
be true and complete on and as of such date with the same force and effect as if
made on and as of such date, and (iii) after giving effect to the waivers and
override provisions set forth in Sections 3 and 4 of this Amendment,
respectively, no Default or Event of Default shall have occurred and be
continuing on such date.

     7. Representations and Warranties. To induce the Administrative Agent and
the Lenders to enter into this Amendment, the Borrowers hereby represent and
warrant to the Administrative Agent and the Lenders that, after giving effect to
the amendments, waivers and override provisions provided for herein, the
representations and warranties contained in the Credit Agreement and the other
Loan Documents will be true and correct in all material respects as if made on
and as of the date hereof and that no Default or Event of Default will have
occurred and be continuing.

     8. Counterparts. This Amendment may be executed by one or more of the
parties hereto on any number of separate counterparts and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument. Delivery of an executed signature page of this Amendment by
facsimile transmission shall be effective as delivery of an executed counterpart
of this Amendment.

     9. Expenses. Each Borrower, jointly and severally, hereby agrees to pay and
reimburse the Administrative Agent for all of the reasonable and documented
out-of-pocket costs and expenses incurred by the Administrative Agent in
connection with the preparation, execution and delivery of this Amendment,
including, without limitation, the fees and disbursements of Cadwalader,
Wickersham & Taft, counsel to the Administrative Agent.

     10. Applicable Law. This Amendment shall be governed by, and construed and
interpreted in accordance with, the laws of the state of New York.


                            [SIGNATURE PAGES FOLLOW]



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<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered as of the day and year first above written.


                                 CELADON GROUP, INC.



                                 By:     /s/ Roger Burbage
                                     -----------------------------------
                                     Name: Roger Burbage
                                     Title:  Sec., Treas.

                                 CELADON TRUCKING SERVICES, INC.



                                 By:     /s/ Roger Burbage
                                      ----------------------------------
                                      Name:  Roger Burbage
                                      Title:  Sec., Treas.


                                 ING CAPITAL LLC (formerly known as ING
                                 (U.S.) CAPITAL LLC), as Administrative
                                 Agent and as a Lender



                                 By:     /s/ Lawrence P. Eyink
                                      -----------------------------------
                                      Name:  Lawrence P. Eyink
                                      Title:  Director



                                      -61-
<PAGE>

         The undersigned Lenders hereby consent and agree to the foregoing
Amendment:.


                                      KEYBANK NATIONAL ASSOCIATION,
                                        as a Lender


                                      By:      /s/ Kevin Hipskind
                                            -----------------------------------
                                             Name:  Kevin Hipskind
                                             Title:  Vice President


                                      NATIONAL BANK OF CANADA,
                                        as a Lender

                                      By:  PNC National Association, its
                                           Attorney-in-Fact


                                      By:      /s/ Colleen A. Logan
                                           ------------------------------------
                                           Name:  Colleen A. Logan
                                           Title:  SVP


                                      UNION PLANTERS BANK, N.A.,
                                        as a Lender


                                        By:     /s/ Thomas W. Craig
                                             ----------------------------------
                                              Name:  Thomas W. Craig
                                              Title:  Vice President


                                      THE NORTHERN TRUST COMPANY,
                                        as a Lender



                                        By:     /s/ Jeffrey B. Clark
                                             ----------------------------------
                                              Name:  Jeffrey B. Clark
                                              Title:  Vice President


                                      FIFTH THIRD BANK, INDIANA,
                                        as a Lender


                                        By:    /s/ Jeffrey Hale
                                             ----------------------------------
                                              Name:  Jeffrey Hale
                                              Title:  Vice President




                                      -62-
<PAGE>

         The undersigned guarantors hereby consent and agree to the foregoing
Amendment:


                                  CELADON TRUCKING SERVICES OF INDIANA, INC.


                                  By:     /s/ Roger Burbage
                                       -------------------------------------
                                       Name:  Roger Burbage
                                       Title:  Sec., Treas.



                                   CELADON TRANSPORTATION, LLP


                                   By:     /s/ Roger Burbage
                                        ------------------------------------
                                        Name:  Roger Burbage
                                        Title:  Sec., Treas.



                                  CHEETAH BROKERAGE CO.


                                  By:     /s/ Roger Burbage
                                        ----------------------------------
                                        Name:  Roger Burbage
                                        Title:  Sec., Treas.



                                   CHEETAH TRANSPORTATION CO.


                                   By:     /s/ Roger Burbage
                                         ---------------------------------
                                          Name:  Roger Burbage
                                          Title:  Sec., Treas.





                                      -63-
<PAGE>

                                    INTERNATIONAL FREIGHT HOLDING CORP.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    JML FREIGHT FORWARDING, INC.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    RIL GROUP, LTD.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    RIL, INC.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    WELLINGMUFT HOLDING CO.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                      -64-
<PAGE>

                                    CELADON LOGISTICS, INC.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    RANDY EXPRESS, LTD.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    RIL ACQUISITION CORP.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    CELADON JACKY MAEDER CO.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.



                                    ZIPP EXPRESS, INC.


                                    By:     /s/ Roger Burbage
                                          ----------------------------------
                                           Name:  Roger Burbage
                                           Title:  Sec., Treas.




                                      -65-
<PAGE>

                                       CELADON E-COMMERCE, INC.


                                       By:     /s/ Roger Burbage
                                             ----------------------------------
                                              Name:  Roger Burbage
                                              Title:  Sec., Treas.



                                       TRUCKERSB2B.COM, INC.


                                       By:     /s/ Roger Burbage
                                            -----------------------------------
                                            Name:  Roger Burbage
                                            Title:  Sec., Treas.





                                      -66-