U.S. Department

of Transportation 400 Seventh St., S.W.

Federal Highway Washington, D.C. 20590

Administration

Refer to: HSA-1/WZ-65

Ms. Denise Mischel

American Fence and Fab. Inc

975 Armour Street

West Fargo, ND 58078

Dear Ms. Mischel: 

Thank you for your letter of December 7 requesting Federal Highway Administration (FHWA)

acceptance of your company’s recycled rubber ballast as a replacement for sandbags on

crashworthy Perforated Square Steel Tube (PSST) Type III barricades for use in work zones on

the National Highway System (NHS). Accompanying your letter was a drawing of the ballast.

You also reference recent crash testing of a PSST Type III barricade by the Midwest Roadside

Safety Facility. This testing was the subject of our acceptance letter to the State of Minnesota,

Number WZ-55, dated December 18, 2000. You requested that we find Type III barricades using

your company’s ballast acceptable for use on the NHS under the provisions of National

Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for

the Safety Performance Evaluation of Highway Features.”

Introduction

FHWA guidance on crash testing of work zone traffic control devices is contained in two

memoranda. The first, dated July 25, 1997, titled “Information: Identifying Acceptable Highway

Safety Features,” established four categories of work zone devices: Category I devices were those

lightweight devices which could be self-certified by the vendor, Category II devices were other

lightweight devices which needed individual crash testing, Category III devices were barriers and

other fixed or massive devices also needing crash testing, and Category IV devices were trailer

mounted lighted signs, arrow panels, etc. The second guidance memorandum was issued on

August 28, 1998, and is titled “INFORMATION: Crash Tested Work Zone Traffic Control

Devices.” This later memorandum lists devices that are acceptable under Categories I, II, and III.

The recycled rubber ballast has a mass of approximately 16 kg (35 pounds) and measures 

768 mm x 355 mm x 57 mm (30.25 x 14 x 2.25 inches). As can be seen in the enclosed drawing

there is a 45 mm wide channel on the bottom of the ballast (parallel to the 355 mm sides) and 

35 mm wide deformations on the top of the ballast. These features interlock to assist storage and

shipping, but also improve the profile of the ballast in use. The 45 mm wide channel on the

bottom fits snugly over a 44 mm (1.75 inch) PSST leg of a Type III barricade. 
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Testing

Full-scale automobile testing has been conducted on various PSST Type III barricades, some

using sand bags as ballast. The bags of sand typically broke on contact with the test vehicle’s

undercarriage spreading sand downrange. This behavior is expected and not a problem. Should a

vehicle undercarriage snag on solid ballasts, or have a wheel ride up on one, vehicle trajectory

may be unpredictable. This is a distinct possibility if the solid ballast projects higher than 100

mm 

(4 inches) above the ground.

Findings

The channel on the underside of your recycled rubber ballast fits over a 44 mm square tube

section, thus maintaining a profile of approximately 100 mm (4 inches) above the ground. This

conforms to the guidance for undercarriage clearance contained in the 1994 American Association

of State Highway and Transportation Officials “Standard Specifications for Structural Supports

for Highway Signs, Luminaires, and Traffic Signals.” We believe this is important to the

acceptable performance of your company’s ballast when used with PSST Type III barricades, or

other crashworthy devices that use 44 mm or smaller PSST legs or rails on the ground. Therefore,

your company’s recycled rubber ballast shown in the enclosed drawings for reference are

acceptable for use as ballast on crashworthy devices having ground-level legs 44 mm wide or

narrower on the NHS under the range of conditions that the crashworthy devices were tested,

when proposed by a State.

Please note the following standard provisions which apply to FHWA letters of acceptance:

! Our acceptance is limited to the crashworthiness characteristics of the devices and does

not cover their structural features, nor conformity with the Manual on Uniform Traffic

Control Devices.

! Any changes that may adversely influence the crashworthiness of the device will require a

new acceptance letter.

! Should the FHWA discover that the qualification testing was flawed, that in-service

performance reveals unacceptable safety problems, or that the device being marketed is

significantly different from the version that was crash tested, it reserves the right to modify

or revoke its acceptance.

! You will be expected to supply potential users with sufficient information on design and

installation requirements to ensure proper performance.

! You will be expected to certify to potential users that the hardware furnished has

essentially the same chemistry, mechanical properties, and geometry as that submitted for

acceptance, and that they will meet the crashworthiness requirements of FHWA and

NCHRP Report 350. 

! To prevent misunderstanding by others, this letter of acceptance, designated as number

WZ-65 shall not be reproduced except in full. This letter, and the test documentation upon

which this letter is based, is public information. All such letters and documentation may

be reviewed at our office upon request.

! Your company’s ballast is patented and considered "proprietary." The use of proprietary

work zone traffic control devices in Federal-aid projects is generally of a temporary nature. 

They are selected by the contractor for use as needed and removed upon completion of the

project. Under such conditions they can be presumed to meet requirement "a" given below
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for the use of proprietary products on Federal-aid projects. On the other hand, if

proprietary devices are specified for use on Federal-aid projects, except exempt, non-NHS

projects, they: (a) must be supplied through competitive bidding with equally suitable

unpatented items; (b) the highway agency must certify that they are essential for

synchronization with existing highway facilities or that no equally suitable alternative

exists or; (c) they must be used for research or for a distinctive type of construction on

relatively short sections of road for experimental purposes. Our regulations concerning

proprietary products are contained in Title 23, Code of Federal Regulations, Section

635.411, a copy of which is enclosed. 

Sincerely yours,

Frederick G. Wright, Jr.

Program Manager, Safety 

Enclosure

Sec. 635.411 Material or product selection. 

(a) Federal funds shall not participate, directly or indirectly, in payment for any premium or

royalty on any patented or proprietary material, specification, or process specifically set forth in

the plans and specifications for a project, unless: 

(1) Such patented or proprietary item is purchased or obtained through competitive bidding with

equally suitable unpatented items; or 

(2) The State highway agency certifies either that such patented or proprietary item is essential

for synchronization with existing highway facilities, or that no equally suitable alternate exists; or 

(3) Such patented or proprietary item is used for research or for a distinctive type of construction

on relatively short sections of road for experimental purposes. 

(b) When there is available for purchase more than one nonpatented, nonproprietary material,

semifinished or finished article or product that will fulfill the requirements for an item of work of

a project and these available materials or products are judged to be of satisfactory quality and

equally acceptable on the basis of engineering analysis and the anticipated prices for the related

item(s) of work are estimated to be approximately the same, the PS&E for the project shall either

contain or include by reference the specifications for each such material or product that is

considered acceptable for incorporation in the work. If the State highway agency wishes to

substitute some other acceptable material or product for the material or product designated by the

successful bidder or bid as the lowest alternate, and such substitution results in an increase in

costs, there will not be Federal-aid participation in any increase in costs. 

(c) A State highway agency may require a specific material or product when there are other

acceptable materials and products, when such specific choice is approved by the Division

Administrator as being in the public interest. When the Division Administrator's approval is not

obtained, the item will be nonparticipating unless bidding procedures are used that establish the

unit price of each acceptable alternative. In this case Federal-aid participation will be based on

the lowest price so established. 

(d) Appendix A sets forth the FHWA requirements regarding (1) the specification of alternative

types of culvert pipes, and (2) the number and types of such alternatives which must be set forth

in the specifications for various types of drainage installations. 

(e) Reference in specifications and on plans to single trade name materials will not be approved

on Federal-aid contracts. 

ENCLOSURE 3