**Exhibit 10(a)**

FIRSTAMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT,

AND REAFFIRMATION OF GUARANTIES

This FIRST AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT ANDREAFFIRMATION OF GUARANTIES, dated as of December 1, 2006 (the “First Amendment”),is entered into by and between QUIXOTE CORPORATION, a Delaware corporation (the“Borrower”), whose address is Thirty Five East Wacker Drive, Chicago, Illinois60601, and QUIXOTE TRANSPORTATION SAFETY, INC., TRANSAFE CORPORATION,ENERGY ABSORPTION SYSTEMS, INC., ENERGY ABSORPTION SYSTEMS (AL) LLC, SURFACESYSTEMS, INC., NU-METRICS, INC., HIGHWAY INFORMATION SYSTEMS, INC., U.S.TRAFFIC CORPORATION (formerly known as Green Light Acquisition Corporation),PEEK TRAFFIC CORPORATION, (formerly known as Vision Acquisition Corporation),as Subsidiary Guarantors, eachbeing referred to herein as a “Guarantor” and collectively referred to hereinas the “Guarantors”), and LASALLE BANK NATIONAL ASSOCIATION, a national bankingassociation (the “Bank”), whose address is 135 South LaSalle Street, Chicago,Illinois 60603.

R E C I T A L S:

A.            TheBorrower and the Bank entered into that certain Amended and Restated CreditAgreement, dated as of April 20, 2005, as modified and amended (collectively,the “Loan Agreement”), pursuant to which Loan Agreement the Bank has made aRevolving Loan to the Borrower evidenced by that certain Revolving Note, datedas of April 20, 2005, in the maximum principal amount of $30,000,000, executedby Borrower and made payable to the order of the Bank.

B.            Inconnection with the Loan Agreement, the Guarantors executed and delivered tothe Bank that certain Guaranty, dated as of May 16, 2003 in favor of the Bank,as amended by that Reaffirmation and Amendment of Subsidiary Guaranty, dated asof April 20, 2005.

C.            Atthe present time the Borrower, the Guarantors and the Bank request (i) that thedefinition of “Letter of Credit be amended to permit on Borrower’s request, byapplication, and the Bank’s issuance of commercial, documentary or tradeLetters of Credit in addition to standby Letters of Credit, and (ii) the Bank’sconsent to the consummation of the Quixote Transportation Technologies, Inc.’s(“QTI”) acquisition of the Mobile IR Sensor product line of Control Products,Inc. (“CPI”) pursuant to the Asset Purchase Agreement, dated as of November 10,2006, between QTI and CPI, pursuant to the terms and conditions hereinafter setforth.

NOW THEREFORE, in consideration of the premises andother good and valuable consideration, the receipt and adequacy of which arehereby acknowledged, the Borrower, and the Guarantors and the Bank hereby agreeas follows:

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A G R E E M E N T S:

1.             RECITALS.  The foregoing Recitals are hereby made a partof this First Amendment.

2.             DEFINITIONS.  Capitalized words and phrases used hereinwithout definition shall have the respective meanings ascribed to such wordsand phrases in the Loan Agreement.

3.             AMENDMENTSTO THE LOAN AGREEMENT.

3.1           RevolvingLoan Commitment.  The definition of “Lettersof Credit” in Section 1.1 of the Loan Agreement is hereby amended in itsentirety to read as follows:

“Letters of Credit” means standby, trade, commercial or documentary letters of credit (i) tobe issued by the Lender, as Lender pursuant to Section 3.1 hereof or (ii)deemed issued by the Lender pursuant to Section 3.2 hereof.

3.2           Section3 of Loan Agreement.  Section 3.7(C)is hereby amended by inserting after standby the following “commercial,documentary or trade (as applicable)”.

3.3           Consentto Acquisition.  The Bank herebyconsents to the acquisition by Quixote Transportation Technologies, Inc. (“QTI”)of the Mobile IR Sensor product line pursuant to the terms of that AssetPurchase Agreement, dated November 10, 2006, between QTI and Control Products,Inc., for a purchase price consisting of (i) a cash payment in the amount of$450,000 at closing, (ii) payment of an earn-out equal to 8% of the net salesprice for products sold by QTI for a four year period after closing; and (iii)QTI’s assumption of certain Assumed Liabilities, as defined therein.

3.4           Releaseof Spin-Cast Plastics, Inc.  Borrowerwarrants that the assets of Spin-Cast Plastics, Inc. (“Spin-Cast”) have beensold and it has been merged into Energy Absorption Systems, Inc.  Spin-Cast is a Guarantor under that certainGuaranty, dated as of May 16, 2003, as amended by that Reaffirmation andAmendment of Subsidiary Guaranty, dated as of April 20, 2005.  The Bank hereby fully and forever releases,withdraws, waives and discharges any and all claims, rights, demands, securityinterests, mortgages, liens, damages, causes of action, judgments orliabilities which the Bank has, had or may have ever had against Spin-Cast,including but not limited to any claims under the Guaranty.

4.             REAFFIRMATIONOF GUARANTIES.  Each of theGuarantors hereby expressly (a) consents to the execution by the Borrower andthe Bank of this First Amendment, (b) acknowledges that the “Guaranteed Debt”(as defined in each of the Guaranties) includes all of the obligations andliabilities owing from the Borrower to the Bank, including, but not limited to,the obligations and liabilities of the Borrower to the Bank under and pursuantto the Loan Agreement, as amended from time to time, and as evidenced by theRevolving Note, as modified, extended and/or replaced from time to time, (c)reaffirms, assumes and binds themselves in all respects to all of theobligations, liabilities, duties, covenants, terms and 

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conditions that are contained in their respective Guaranty, (d) agreesthat all such obligations and liabilities under their respective Guaranty shallcontinue in full force and effect and shall not be discharged, limited,impaired or affected in any manner whatsoever, and (e) represents and warrantsthat each of the representations and warranties made by such Guarantor in anyof the documents executed in connection with the Loans remain true and correctas of the date hereof.

5.             REPRESENTATIONSAND WARRANTIES.  To induce the Bankto enter into this First Amendment, the Borrower hereby certifies, representsand warrants to the Bank that:

5.1           Organization.  The Borrower is a corporation duly organized,existing and in good standing under the laws of the State of Delaware with fulland adequate corporate power to carry on and conduct its business as presentlyconducted.  The Borrower is duly licensedor qualified in all foreign jurisdictions wherein the nature of its activitiesrequire such qualification or licensing. The Articles of Incorporation andBylaws, Borrowing Resolutions and Incumbency Certificate of the Borrower havenot been changed or amended since the most recent date that certified copiesthereof were delivered to the Bank, except as amended (i) to increase thenumber of directors and to provide for certificated and uncertificated shares,as incorporated in the By-Laws, and (ii) to increase the number of authorizedshares, as incorporated in the Articles of Incorporation, both of which aredelivered by Borrower hereunder.  TheBorrower’s state issued organizational identification number is ________ [state“None” if the Borrower’s state of organization does not issue such anumber].  The exact legal name of theBorrower is as set forth in the preamble of this First Amendment, and theBorrower currently does not conduct, nor has it during the last five (5) yearsconducted, business under any other name or trade name.  The Borrower will not change its name, itsorganizational identification number, if it has one, its type of organization,its jurisdiction of organization or other legal structure.

5.2           Authorization.  The Borrower is duly authorized to executeand deliver this First Amendment and is and will continue to be duly authorizedto borrow monies under the Loan Agreement, as amended hereby, and to performits obligations under the Loan Agreement, as amended hereby.

5.3           NoConflicts.  The execution anddelivery of this First Amendment and the performance by the Borrower of itsobligations under the Loan Agreement, as amended hereby, do not and will notconflict with any provision of law or of the articles of incorporation orbylaws of the Borrower or of any agreement binding upon the Borrower.

5.4           Validityand Binding Effect.  The LoanAgreement, as amended hereby, is a legal, valid and binding obligation of theBorrower, enforceable against the Borrower in accordance with its terms, exceptas enforceability may be limited by bankruptcy, insolvency or other similarlaws of general application affecting the enforcement of creditors’ rights orby general principles of equity limiting the availability of equitableremedies.

5.5           Compliancewith Loan Agreement.  Therepresentation and warranties set forth in Section VI of the Loan Agreement, asamended hereby, are true and correct with the same effect as if suchrepresentations and warranties had been made on the date hereof, with the 

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exception that all references to the financial statements shall meanthe financial statements most recently delivered to the Bank and except forsuch changes as are specifically permitted under the Loan Agreement.  In addition, the Borrower has complied withand is in compliance with all of the covenants set forth in the Loan Agreement,as amended hereby, including, but not limited to, those set forth in SectionVII thereof.

5.6           NoEvent of Default.  As of the datehereof, no Event of Default under Section VIII of the Loan Agreement, asamended hereby, or event or condition which, with the giving of notice or thepassage of time, or both, would constitute an Event of Default, has occurred oris continuing.

5.7           NoSubordinated Debt Default.  As of thedate hereof, no default under any of the documents evidencing or securing anyof the Junior Debt, or event or condition which, with the giving of notice orthe passage of time, or both, would constitute a default under any of thedocuments evidencing or securing any of the Subordinated Debt, has occurred oris continuing.

6.             CONDITIONSPRECEDENT.  This First Amendmentshall become effective as of the date above first written after receipt by theBank of the following documents:

6.1           FirstAmendment.  This First Amendment executedby the Borrower, the Guarantors, and the Bank.

6.2           By-Lawsand Certificate of Incorporation. Copies of By-Laws and Certificate ofIncorporation of Borrower, which Borrower certifies are true, complete and infull force and effect as of the date hereof, it being understood that the Bankmay conclusively rely on each such document until formally advised by Borrowerof any changes therein.

6.3           OtherDocuments.  Such other documents,certificates and/or opinions of counsel as the Bank may request.

7.             GENERAL.

7.1           GoverningLaw; Severability.  This FirstAmendment shall be construed in accordance with and governed by the laws ofIllinois.  Wherever possible eachprovision of the Loan Agreement and this First Amendment shall be interpretedin such manner as to be effective and valid under applicable law, but if anyprovision of the Loan Agreement and this First Amendment shall be prohibited byor invalid under such law, such provision shall be ineffective to the extent ofsuch prohibition or invalidity, without invalidating the remainder of suchprovision or the remaining provisions of the Loan Agreement and this FirstAmendment.

7.2           Successorsand Assigns.  This First Amendmentshall be binding upon the Borrower, the Guarantors, and the Bank and theirrespective successors and assigns, and shall inure to the benefit of theBorrower, the Guarantors, and the Bank and the successors and assigns of theBank.

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7.3           ContinuingForce and Effect of Loan Documents and Guaranty.  Except as specifically modified or amended bythe terms of this First Amendment, all other terms and provisions of the LoanAgreement and the other Loan Documents are incorporated by reference herein,and in all respects, shall continue in full force and effect.  The Borrower, by execution of this FirstAmendment, hereby reaffirms, assumes and binds itself to all of theobligations, duties, rights, covenants, terms and conditions that are containedin the Loan Agreement and the other Loan Documents.  Each of the Guarantors, by execution of thisFirst Amendment, hereby reaffirms, assumes and binds itself to all of theobligations, duties, rights, covenants, terms and conditions that are containedin Guaranty.

7.4           FinancingStatements.  The Borrower herebyirrevocably authorizes the Bank at any time and from time to time to file inany jurisdiction any initial UCC financing statements and/or amendments theretothat (a) describe the Collateral, and (b) contain any other informationrequired by part 5 of Article 9 of the UCC for the sufficiency or filing officeacceptance of any financing statement or amendment.

7.5           Referencesto Loan Agreement.  Each reference inthe Loan Agreement to “this Agreement”, “hereunder”, “hereof”, or words of likeimport, and each reference to the Loan Agreement in any and all instruments ordocuments delivered in connection therewith, shall be deemed to refer to theLoan Agreement, as amended hereby.

7.6           Expenses.  The Borrower shall pay all costs and expensesin connection with the preparation of this First Amendment and other relatedloan documents, including, without limitation, reasonable attorneys’ fees andtime charges of attorneys who may be employees of the Bank or any affiliate orparent of the Bank.  The Borrower shallpay any and all stamp and other taxes, UCC search fees, filing fees and othercosts and expenses in connection with the execution and delivery of this FirstAmendment and the other instruments and documents to be delivered hereunder,and agrees to save the Bank harmless from and against any and all liabilitieswith respect to or resulting from any delay in paying or omission to pay suchcosts and expenses.

7.7           Counterparts.  This First Amendment may be executed in anynumber of counterparts, all of which shall constitute one and the sameagreement.

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IN WITNESS WHEREOF, the parties hereto have executedthis First Amendment to Amended and Restated Credit Agreement and Reaffirmationof Guaranties as of the date first above written.
|        | QUIXOTE CORPORATION                                                                                      |
|--------|----------------------------------------------------------------------------------------------------------|
|   | a Delaware corporation, as Borrower                                                                      |
|   |                                                                                                     |   |
|   |                                                                                                     |   |
|   | By:                                                                                                      | /s/ Daniel P. Gorey |
|   | Name:                                                                                                    | Daniel P. Gorey |
|   | Title:                                                                                                   | Vice President, Chief Financial Officer |
|   |                                                                                                     | and Treasurer |
|   |                                                                                                     |   |
|   |                                                                                                     |   |
|   | QUIXOTE TRANSPORTATION SAFETY, INC.                                                                      |
|   | TRANSAFE CORPORATION                                                                                     |
|   | ENERGY ABSORPTION SYSTEMS, INC.                                                                          |
|   | ENERGY ABSORPTION SYSTEMS (AL) LLC                                                                       |
|   | SURFACE SYSTEMS, INC.                                                                                    |
|   | NU-METRICS, INC.                                                                                         |
|   | HIGHWAY INFORMATION SYSTEMS, INC.                                                                        |
|   | U.S. TRAFFIC CORPORATION                                                                                 |
|   | (formerly known as Green Light Acquisition  Corporation)                                                 |
|   | PEEK TRAFFIC CORPORATION, (formerly  known as Vision Acquisition Corporation), as  Subsidiary Guarantors |
|   |                                                                                                     |   |
|   |                                                                                                     |   |
|   | Name:                                                                                                    | Daniel P. Gorey |
|   | Title:                                                                                                   | Vice President and Treasurer |
|   |                                                                                                     |   |
|   |                                                                                                     |   |
|   | LASALLE BANK NATIONAL ASSOCIATION,                                                                       |
|   | a national banking association                                                                           |
|   |                                                                                                     |   |
|   |                                                                                                     |   |
|   | By:                                                                                                      | /s/ Loran Backofen |
|   | Name:                                                                                                    | Lora Backofen |
|   | Title:                                                                                                   | Senior Vice President |
|        |                                                                                                          |  |  |  |

 

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