Refer to: HSA-10/SS-114

Mr. Darren Hesse 

National Sales Manager 

S-Square Tube Products 

5495 East 69th Avenue 

Commerce City, Colorado 80022 

Dear Mr. Hesse: 

Thank you for your July 12, 2002, letter to Mr. Nicholas Artimovich requesting Federal 

Highway Administration (FHWA) acceptance of your company=s NEX Tube as a 

breakaway component of a crashworthy mailbox support for use on the National 

Highway System (NHS). Accompanying your letter were photographs of your proposed 

mailbox mounting systems. You requested that we find the NEX Tube Mailbox Support 

System acceptable for use on the National Highway System under the provisions of 

National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended 

Procedures for the Safety Performance Evaluation of Highway Features.” On October 

12, 2002, you provided additional information on a redesigned support for 

accommodating multiple mailboxes. 

Introduction 

Pendulum and full-scale automobile testing of NEX Tube sign supports was completed in 

1998, and was in compliance with the guidelines contained in the NCHRP Report 350, 

Recommended Procedures for the Safety Performance Evaluation of Highway Features. 

Requirements for breakaway supports are those in the American Association of State 

Highway and Transportation Officials' Standard Specifications for Structural Supports for 

Highway Signs, Luminaires and Traffic Signals. Our Acceptance Letter, SS-81, found 

the NEX Tube sign supports acceptable for use on the NHS. 

The NEX Tube mailboxes use the same deformed cross-section 14 gage steel pipe, 

formed into what might be called a “question mark” shape. The base of the support is 

inserted into a ground socket and secured with a wedge. Drawings of the supports are 

enclosed for reference. 

Findings 

The testing of the NEX Tube sign supports showed that the socket and wedge 

arrangement was a successful breakaway design, with vehicle velocity changes well 

below the desirable limit of 3 m/sec for single supports and approximately 3 m/s for a 
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dual post support. You asked that we compare your socket design to the V-Loc system, 

which has already been tested as a mailbox support. We concur with your assertion that 

the same technology will be effective as a single/double mailbox support. Therefore, the 

NEX Tube sign support will be acceptable for use as a single/double mailbox support 

using the socket and wedge design as shown in the enclosed drawings. 

You also asked that we accept the NEX tube for use with multiple mailboxes using the 

“inverted coat hanger” arrangement. When the V-Loc system was tested with a multiple 

mailbox support (using 14 gage steel pipe in an “inverted coat hanger” arrangement) the 

occupant impact speeds were almost at the limit of acceptability. Because your design 

did not replicate the basic “closed loop” shape of the V-loc system, we were not as 

certain that five-box support using the NEX tube would meet the occupant impact 

velocity requirements. You have since redesigned your multiple mailbox support to 

replicate the “inverted coat hanger” arrangement, which we expect will perform in an 

acceptable manner. 

The single/double mailbox support and the “inverted coat hanger” multiple mailbox 

support described above and shown in the enclosed drawings for reference are acceptable 

for use as Test Level 3 devices on the NHS under the range of conditions tested, when 

proposed by a State. The single box supports are considered crashworthy for 

conventional rural mailboxes weighing up to 5 pounds. The multiple box supports are 

considered crashworthy when boxes weighing up to 3.5 pounds each, are used. 

Please note the following standard provisions that 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 SS-114 shall not be reproduced except in full. As this letter and the 

supporting documentation which support it become public information, it will be 

available for inspection at our office by interested parties. 

! The Nex Tube is a patented product and is considered "proprietary." The use of 

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

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

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

Carol H. Jacoby, P.E. 

 Director, Office of Safety Design 

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 2