Exhibit 10.11.3

THIRD AMENDMENT TO, AND WAIVER UNDER, CREDIT AGREEMENT

THIS THIRD AMENDMENT TO, AND WAIVER UNDER, CREDIT AGREEMENT (this “ Third Amendment ”) is made and entered into as of December 29, 2006, by and among the financial institutions identified on the signature pages hereof (such financial institutions, together with their respective successors and assigns, are referred to hereinafter each individually as a “ Lender ” and collectively as the “ Lenders ”), WELLS FARGO FOOTHILL, INC., a California corporation, as arranger and administrative agent for the Lenders (in such capacities, together with any successor arranger and administrative agent, “ Agent ”), and TRC COMPANIES, INC., a Delaware corporation (the “ Administrative Borrower ”), on behalf of all Borrowers.

WITNESSETH :

WHEREAS, the Administrative Borrower, the Administrative Borrower’s Subsidiaries party thereto, the Lenders and Agent are parties to that certain Credit Agreement, dated as of July 17, 2006 (as amended as of October 31, 2006 (the “ First Amendment ”) and as of November 29, 2006, and as the same may be amended, modified, supplemented or amended and restated from time to time, the “ Credit Agreement ”);

WHEREAS, Section 3.6(b) of the Credit Agreement (as amended by the First Amendment) required that, on or prior to December 15, 2006, Agent shall have received a Collateral Access Agreement with respect to the locations listed on Schedule 3.6(b) to the Credit Agreement (the “ Section 3.6(b) Requirement ”);

WHEREAS, the Section 3.6(b) Requirement has not yet been completely satisfied (the “ Section 3.6(b) Default ”);

WHEREAS, the Administrative Borrower has requested, and Agent and the Lenders have agreed, to waive the Section 3.6(b) Default, subject to the terms and conditions set forth herein; and

WHEREAS, Agent, the Lenders and the Borrowers wish to amend the Credit Agreement as herein provided;

NOW, THEREFORE, in consideration of the agreements and provisions herein contained, the parties hereto do hereby agree as follows:

Section 1.   Definitions .   Any capitalized terms used but not otherwise defined herein shall have the meanings ascribed to such terms in the Credit Agreement.

Section 2.   Waiver Under Credit Agreement .   Subject to the satisfaction of the terms and conditions set forth herein, Agent and the Required Lenders hereby waive the Section 3.6(b) Default, provided , that the foregoing waiver shall be rescinded and no longer effective as of January 31, 2007 if the Administrative Borrower fails to deliver to Agent Collateral Access

Agreements with respect to all of the locations listed on Schedule 3.6(b) to the Credit Agreement, on or prior to January 31, 2007.

Section 3.   Amendments to Credit Agreement .  Subject to the terms and conditions set forth herein, the Credit Agreement is hereby amended, as of the Effective Date (defined below), as follows:

3.01   Amendment to Schedule 5.3 .  The left hand column in the second row of the table in Schedule 5.3 to the Credit Agreement is hereby amended by deleting the words “on or prior to December 31, 2006” therein and inserting “on or prior to January 31, 2007” in lieu thereof.

Section 4.   Representations and Warranties .  In order to induce Agent and the Lenders to enter into this Third Amendment, the Administrative Borrower, for itself and on behalf of all of the other Borrowers, hereby represents and warrants that:

4.01   No Default .   At and as of the date of this Third Amendment and at and as of the Effective Date and both prior to (other than with respect to the Section 3.6(b) Default) and after giving effect to this Third Amendment, no Default or Event of Default exists and is continuing.

4.02   Representations and Warranties True and Correct .   At and as of the date of this Third Amendment and both prior to (other than with respect to the Section 3.6(b) Default) and after giving effect to this Third Amendment, each of the representations and warranties contained in the Credit Agreement and other Loan Documents is true and correct in all material respects.

4.03   Corporate Power, Etc.   Administrative Borrower (a) has all requisite corporate power and authority to execute and deliver this Third Amendment and to consummate the transactions contemplated hereby for itself and, in the case of Administrative Borrower, on behalf of all of the other Borrowers, and (b) has taken all action, corporate or otherwise, necessary to authorize the execution and delivery of this Third Amendment and the consummation of the transactions contemplated hereby for itself and, in the case of Administrative Borrower, on behalf of all of the other Borrowers.

4.04   No Conflict .   The execution, delivery and performance by Administrative Borrower (on behalf of itself and all of the other Borrowers) of this Third Amendment will not (a) violate any provision of federal, state, or local law or regulation applicable to any Borrower, the Governing Documents of any Borrower, or any order, judgment or decree of any court or other Governmental Authority binding on any Borrower, (b) conflict with or result in any breach of, or constitute (with due notice or laps