Refer to: HSA-10/SS-107

Mr. Richard W. Sargent

Town of Waterford

Department of Public Works

15 Rope Ferry Road

Waterford, CT 06385

Dear Mr. Sargent:

Thank you for your letter of February 14, 2002, requesting Federal
Highway Administration (FHWA) acceptance of 2 pound-per-foot (PPF)
U-channel posts as a breakaway sign support system for use on the
National Highway System (NHS). You requested that we find 2 PPF posts
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**

Testing of sign supports is done under 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\' (AASHTO) Standard Specifications for Structural Supports for
Highway Signs, Luminaires and Traffic Signals.

**Testing**

Full-scale automobile testing under current guidelines was conducted on
direct-bury 3 pound-per-foot U-channel post sign supports in strong soil
in 1985. This system was found acceptable in FHWA Acceptance Letter
SS-5, dated June 15, 1987. Subsequently, various

3- and 4- pound-per-foot U-channel breakaway sign support systems have
been tested and found acceptable for installations where more than two
3-PPF posts are needed, and where weaker soils are encountered. These
systems include specialized hardware such as splice bolts, spacers, slip
bases, soil plates, etc. These systems also are favored by some
jurisdictions because they reduce the level of effort needed to replace
or repair a damaged installation.

The FHWA considers steel sign posts that are lighter gage than the
crash-tested posts, both

U-channel and perforated square steel tube supports, as acceptable for
use.

**Findings**

Two pound-per-foot U-channel sign supports conforming to the crashworthy
designs of 3- and

4-PPF supports, formed of re-rolled rail steel, or new billet steel
meeting the same requirements as rail steel, are acceptable for use as
Test Level 3 devices on the NHS under the range of conditions tested,
when proposed by a State. The material specifications for the U-channel
posts used in crashworthy supports are contained in FHWA Technical
Advisory T5040.22 "Steel Flanged Channel Posts of Small Highway Sign
Supports," dated September 27, 1983. A copy of this technical advisory
is enclosed for your information.

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-107 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.

> Sincerely yours,
>
> A. George Ostensen

Program Manager, Safety

Enclosure

FHWA:HSA-10:NArtimovich:tb:x61331:4/4/02

File: SS107Waterford2PPF.wpd

cc: HSA-10 (Reader, HSA-1; Chron File, HSA-10;

N. Artimovich, HSA-10)