Exhibit 10.(a)  FOURTH AMENDMENT TO AMENDED AND RESTATED
CREDIT AGREEMENT AND REAFFIRMATION OF GUARANTIES  THIS
FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT AND REAFFIRMATION OF
GUARANTIES, dated as of November 7, 2008 (the Fourth
Amendment), is entered into by and between Quixote Corporation, a
Delaware corporation (the Borrower),
whose address is 35 East Wacker Drive, Chicago, Illinois 60601, and Quixote
Transportation Safety, Inc., Transafe Corporation, Energy Absorption
Systems, Inc., Energy Absorption Systems (AL) LLC, Surface Systems, Inc.,
Nu-Metrics, Inc., and Highway Information Systems, Inc., as
Subsidiary Guarantors, (each being referred to herein as a Guarantor and collectively referred to herein as the Guarantors), and Bank of America, N.A., as successor by
merger to LaSalle Bank National Association, a national banking association
(the Lender), whose address is 135 South
LaSalle Street, Chicago, Illinois 60603.  RECITALS:  A.Borrower and Lender entered into that certain
Amended and Restated Credit Agreement, dated as of April 20, 2005 (the Original Credit Agreement), as amended by that certain
First Amendment to Amended and Restated Credit Agreement and Reaffirmation of
Guaranties dated as of December 1, 2006, (the First
Amendment), that certain Second Amendment to Amended and Restated
Credit Agreement and Reaffirmation of Guaranties dated as of March 15,
2007 (the Second Amendment) and that
certain Third Amendment to Amended and Restated Credit Agreement and Reaffirmation
of Guaranties dated as of November 7, 2007 (the Third
Amendment, and together with the Original Credit Agreement, the
First Amendment and the Second Amendment, the Credit
Agreement) pursuant to which Credit Agreement Lender has made a
Revolving Loan to Borrower evidenced by that certain Amended and Restated
Revolving Loan Note, dated as of November 7, 2007, in the maximum
principal amount of $40,000,000, executed by Borrower and made payable to the
order of Lender (the Revolving Note).  B.In connection with the Original Credit
Agreement, the Guarantors executed and delivered to Lender that certain
Guaranty dated as of May 16, 2003 in favor of Lender, as amended by that
Reaffirmation and Amendment of Subsidiary Guaranty dated as of April 20,
2005 (the Guaranty).  C.At the present time Borrower and the
Guarantors request, and Lender is agreeable to, the modification of certain
terms contained in the Credit Agreement as set forth herein, all pursuant to
the terms and conditions hereinafter set forth.  NOW
THEREFORE, in consideration of the premises and other good and valuable
consideration, the receipt and adequacy of which are hereby acknowledged,
Borrower, the Guarantors and Lender hereby agree as follows:  AGREEMENTS:  1.RECITALS.  The foregoing Recitals are
hereby made a part of this Fourth Amendment.  2.DEFINITIONS.  Capitalized words and phrases
used herein without definition shall have the respective meanings ascribed
thereto in the Credit Agreement.  3.AMENDMENTS TO THE CREDIT AGREEMENT.


3.1Section 1.1 of the Credit Agreement.  (a)The
definition of Alternate Base Rate in Section 1.1 of the Credit Agreement
is hereby deleted in its entirety and restated as follows:  Alternate
Base Rate means a fluctuating rate of interest equal to the rate per annum
equal to the British Bankers Association LIBOR Rate (BBA LIBOR), as published
by Reuters (or other commercially available source providing quotations of BBA
LIBOR as selected by the Lender from time to time) as determined for each banking
day at approximately 11:00 a.m. London time two (2) Business Days (or
three Business Days prior to the commencement of such Interest Period if banks
in London, England were not open and dealing in offshore Dollars on such second
preceding Business Day) prior to the date in question, for Dollar deposits (for
delivery on the first day of such Interest Period) with a one month term, as
adjusted from time to time in the Lenders sole discretion for reserve
requirements, deposit insurance assessment rates and other regulatory
costs.  If such rate is not available at
such time for any reason, then the rate for that interest period will be
determined by such alternate method as reasonably selected by the Lender.  The Lenders determination of BBA Libor shall
be conclusive absent manifest error.  3.2Section 2.13
of the Credit Agreement.  Section 2.13(D)(ii) is hereby
amended by deleting the existing pricing grid in its entirety and replacing it
with the following:  Level
  
  Maximum
  Total Leverage
  Ratio
  
  Applicable
  Eurodollar
  Margin/L/C Fee
  Percentage
  
  Applicable ABR
  Margin
  
  Commitment
  Fee
  PercentageV
  
  >3.00
  
  2.25
  %
  2.25
  %
  0.50
  %IV
  
  >2.50 BUT
  <3.00
  
  2.00
  %
  2.00
  %
  0.50
  %III
  
  >2.00 BUT
  <2.50
  
  1.75
  %
  1.75
  %
  0.375
  %II
  
  >1.50 BUT
  <2.00
  
  1.50
  %
  1.50
  %
  0.375
  %I
  
  <1.50
  
  1.25
  %
  1.25
  %
  0.375
  %  3.3Section 7.4
of the Credit Agreement.  The introductory language of Section 7.4of
the Credit Agreement is hereby deleted in its entirety and restated as follows:  7.4Financial Covenants.  The
Borrower shall comply with the financial covenants set forth below.  Solely for the purposes of calculating the
financial covenants, consolidated Subsidiaries of Borrower shall exclude U.S.
Traffic Corporation and Peek Traffic Corporation.  4.REAFFIRMATION OF GUARANTIES.  Each
of the Guarantors hereby expressly (a) consents to the execution by
Borrower and Lender of this Fourth Amendment, (b) acknowledges that the Guaranteed
Debt (as defined in each of the Guaranties) includes all of the obligations
and liabilities  2


owing
from Borrower to Lender, including, but not limited to, the obligations and
liabilities of Borrower to Lender under and pursuant to the Credit Agreement,
as amended from time to time, and as evidenced by the Revolving Note, as
modified, extended and/or replaced from time to time, (c) reaffirms,
assumes and binds themselves in all respects to all of the obligations,
liabilities, duties, covenants, terms and conditions that are contained in
their respective Guaranty, (d) agrees that all such obligations and
liabilities under their respective Guaranty shall continue in full force and
effect and shall not be discharged, limited, impaired or affected in any manner
whatsoever, and (e) represents and warrants that each of the
representations and warranties made by such Guarantor in any of the documents
executed in connection with the Loans remain true and correct as of the date
hereof.  5.REPRESENTATIONS AND WARRANTIES.  To
induce Lender to enter into this Fourth Amendment, Borrower and each Guarantor
hereby certifies, represents and warrants to Lender that:  5.1Organization. 
Borrower and each Guarantor is a corporation or a limited liability
company duly organized, existing and in good standing under the laws of its
state or organization with full and adequate corporate or limited liability
power, as the case may be, to carry on and conduct its business as presently
conducted.  Other than as shown on
Schedule I hereto, Borrower and each Guarantor is duly licensed or qualified in
all foreign jurisdictions wherein the nature of its activities require such
qualification or licensing.  The Articles
of Incorporation or Organization, as the case may be, Bylaws (other than an amendment
to the By-laws of Borrower dated July 24, 2008) or Operating Agreement, as
the case may be, Resolutions and Incumbency Certificate of Borrower and each
Guarantor have not been changed or amended since the certified copies thereof
were delivered to Lender in connection with the Original Credit Agreement and
the First Amendment.  The state issued
organizational identification number for Borrower and each Guarantor is listed
on Schedule I hereto.  The exact
legal name of Borrower and each Guarantor is as set forth in the preamble of
this Fourth Amendment, and neither Borrower nor any Guarantor currently
conducts, nor has it during the last five (5) years conducted, business
under any other name or trade name. 
Neither Borrower nor any Guarantor will change its name, its
organizational identification number, if it has one, its type of organization,
its jurisdiction of organization or other legal structure.  5.2Authorization. 
Borrower and each Guarantor is duly authorized to execute and deliver
this Fourth Amendment and Borrower is and will continue to be duly authorized
to borrow monies under the Credit Agreement, as amended hereby, and to perform
its obligations under the Credit Agreement, as amended hereby.  5.3No
Conflicts.  The execution and delivery of this Fourth
Amendment and the performance by Borrower and each Guarantor of its obligations
under the Credit Agreement, as amended hereby, do not and will not conflict
with any provision of law or of the articles of incorporation or bylaws of
Borrower or any Guarantor or of any agreement binding upon Borrower or any
Guarantor.  5.4Validity
and Binding Effect.  The Credit Agreement, as amended hereby, is a
legal, valid and binding obligation of Borrower and each Guarantor, enforceable
against Borrower and each Guarantor in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency or other similar laws
of general application affecting the enforcement of creditors rights or by
general principles of equity limiting the availability of equitable remedies.  3


5.5Compliance with Credit Agreement.  The
representation and warranties set forth in Section VI of the Credit
Agreement, as amended hereby, are true and correct with the same effect as if
such representations and warranties had been made on the date hereof, with the
exception that all references to the financial statements shall mean the
financial statements most recently delivered to Lender and except for such
changes as are specifically permitted under the Credit Agreement.  In addition, Borrower and each Guarantor has
complied with and is in compliance with all of the covenants set forth in the
Credit Agreement, as amended hereby, including, but not limited to, those set
forth in Section VII thereof.  5.6No
Event of Default.  As of the date hereof, no Event of Default
under Section VII of the Credit Agreement, as amended hereby, or event or
condition which, with the giving of notice or the passage of time, or both,
would constitute an Event of Default, has occurred or is continuing.  5.7No
Subordinated Debt Default.  As of the date hereof, no default under any
of the documents evidencing or securing any of the Subordinated Debt, or event
or condition which, with the giving of notice or the passage of time, or both,
would constitute a default under any of the documents evidencing or securing
any of the Subordinated Debt, has occurred or is continuing.  5.8Schedules
to Credit Agreement.  Other than as shown by the updated Schedules
attached hereto as Exhibit A, the Schedules attached to the Credit Agreement
are true and correct as of the date hereof.  6.CONDITIONS PRECEDENT.  This
Fourth Amendment shall become effective as of the date above first written
after receipt by Lender of the following documents:  6.1Fourth
Amendment.  This Fourth Amendment executed by Borrower,
the Guarantors, and Lender.  6.2Resolutions.  A
certified copy of Resolutions of the board of directors of Borrower and each
Guarantor authorizing the execution, delivery and performance of this Fourth
Amendment and related loan documents.  6.3Certificate
of Good Standing.  Certificates of Good Standing for Borrower
and each Guarantor from their respective jurisdictions of organization.  6.4Other
Documents.  Such other documents, certificates and/or
opinions of counsel as Lender may request.  7.GENERAL.  7.1Governing
Law; Severability.  This Fourth Amendment shall be construed in
accordance with and governed by the laws of Illinois.  Wherever possible each provision of the
Credit Agreement and this Fourth Amendment shall be interpreted in such manner
as to be effective and valid under applicable law, but if any provision of the
Credit Agreement and this Fourth Amendment shall be prohibited by or invalid
under such law, such provision shall be ineffective to the extent of such
prohibition or invalidity, without invalidating the remainder of such provision
or the remaining provisions of the Credit Agreement and this Fourth Amendment.  7.2Successors
and Assigns.  This Fourth Amendment shall be binding upon
Borrower, the Guarantors, and Lender and their respective successors and
assigns, and shall inure to the benefit of Borrower, the Guarantors, and Lender
and the successors and assigns of Lender.  4


7.3Waiver
of Claims.  Borrower hereby acknowledges, agrees and
affirms that it possesses no claims, defenses, offsets, recoupment or
counterclaims of any kind or nature against or with respect to the enforcement
of the Credit Agreement, as amended hereby, the Revolving Note or any other
Loan Document (collectively referred to herein as the Claims),
nor does Borrower now have knowledge of any facts that would or might give rise
to any Claims.  If facts now exist which
would or could give rise to any Claim against or with respect to the
enforcement of the Credit Agreement as amended hereby, the Revolving Note,
and/or any other Loan Documents, Borrower hereby unconditionally, irrevocably
and unequivocally waives and fully releases any and all such Claims as if such
Claims were the subject of a lawsuit, adjudicated to final judgment from which
no appeal could be taken and therein dismissed with prejudice.  7.4Continuing
Force and Effect of Loan Documents and Guaranty. 
Except as specifically modified or amended by the terms of this Fourth
Amendment, all other terms and provisions of the Credit Agreement and the other
Loan Documents are incorporated by reference herein, and in all respects, shall
continue in full force and effect. 
Borrower, by execution of this Fourth Amendment, hereby reaffirms,
assumes and binds itself to all of the obligations, duties, rights, covenants,
terms and conditions that are contained in the Credit Agreement and the other
Loan Documents.  Each of the Guarantors,
by execution of this Fourth Amendment, hereby reaffirms, assumes and binds
itself to all of the obligations, duties, rights, covenants, terms and
conditions that are contained in Guaranty.  7.5Financing Statements. 
Borrower hereby irrevocably authorizes Lender at any time and from time
to time to file in any jurisdiction any initial UCC financing statements and/or
amendments thereto that (a) describe the Collateral, and (b) contain
any other information required by part 5 of Article 9 of the UCC for the
sufficiency or filing office acceptance of any financing statement or
amendment.  7.6References
to Credit Agreement.  Each reference in the Credit Agreement to this
Agreement, hereunder, hereof, or words of like import, and each reference
to the Credit Agreement in any and all instruments or documents delivered in
connection therewith, shall be deemed to refer to the Credit Agreement, as
amended hereby.  7.7Expenses. 
Borrower shall pay all costs and expenses in connection with the
preparation of this Fourth Amendment and other related loan documents,
including, without limitation, reasonable attorneys fees and time charges of
attorneys who may be employees of Lender or any affiliate or parent of
Lender.  Borrower shall pay any and all
stamp and other taxes, UCC search fees, filing fees and other costs and
expenses in connection with the execution and delivery of this Fourth Amendment
and the other instruments and documents to be delivered hereunder, and agrees
to save Lender harmless from and against any and all liabilities with respect
to or resulting from any delay in paying or omission to pay such costs and
expenses.  7.8Counterparts.  This
Fourth Amendment may be executed in any number of counterparts, all of which
shall constitute one and the same agreement.  [Signatures on following page]  5


IN
WITNESS WHEREOF, the parties hereto have executed this Fourth Amendment to the
Amended and Restated Credit Agreement and Reaffirmation of Guaranties as of the
date first above written.   Borrower:QUIXOTE CORPORATION,a Delaware corporation, as
  BorrowerBy:
  /s/
  DANIEL P. GOREYName:
  Daniel
  P. GoreyTitle:
  Vice
  President, Chief Financial Officer & TreasurerGuarantors:QUIXOTE TRANSPORTATION
  SAFETY, INC. 
  TRANSAFE CORPORATIONENERGY
  ABSORPTION SYSTEMS, INC.ENERGY ABSORPTION SYSTEMS
  (AL) LLC 
  SURFACE SYSTEMS, INC.NU-METRICS,
  INC.HIGHWAY
  INFORMATION SYSTEMS, INC.By:
  /s/ DANIEL P. GOREYName:
  Daniel
  P. GoreyTitle:
  Vice
  President & TreasurerLender:Bank of America, N.A., as
  successor by merger to 
  LaSalle Bank National Association, a national banking 
  associationBy:
  /s/
  LORA BACKOFENName:
  Lora
  BackofenTitle:
  Sr. Vice President  6


Schedule
I  Qualification Issues   Energy Absorption
Systems, Inc. is not currently in good standing in the State of
California.  Energy Absorption Systems (AL)
LLC is not currently in good standing in the State of Alabama.  7


Schedule II  Organizational Identification Numbers  CORPORATION
  
  STATE
  
  STATE IDQuixote Corporation
  
  Delaware
  
  0720523Quixote Transportation Safety, Inc.
  
  Delaware
  
  2803660Transafe Corporation
  
  Delaware
  
  3197646Energy Absorption Systems, Inc.
  
  Delaware
  
  0904033Energy Absorption (AL) LLC
  
  Delaware
  
  3539333Surface Systems, Inc.
  
  Missouri
  
  00157025Nu-Metrics, Inc.
  
  Pennsylvania
  
  978728Highway Information Systems, Inc.
  
  Delaware
  
  2867376  8