1200 New Jersey Ave., SE

 Washington, D.C. 20590

November 23, 2011

FHWA: HSST: NArtimovich:ms:x61331:11/9/11

File: h://directory folder/HSST/SS-174_Trinity.docx

cc: HSST (Reader, HSA; Chron File, HSST; NArtimovich, HSST; 

 , HSST; MGriffith, HSST) 

In Reply Refer To:

HSST/ SS-174

T.J. Aslin

Trinity Highway Products, LLC

2525 Stemmons Freeway

Dallas, Texas 75207

Dear Mr. Aslin:

This letter is in response to your request for the Federal Highway Administration (FHWA) 

determination of eligibility for reimbursement under the Federal-aid highway program for 

highway safety products formerly manufactured by Northwest Pipe Company.

Name of system: Breakaway Sign Support Systems of Northwest Pipe Company

Type of system: Breakaway Sign Supports

Test Level: NCHRP Report 350 Test Level 3

Testing conducted by: Various

Date of request: October 10, 2011

Date initially acknowledged: November 3, 2011

You certify that the devices described herein meet the crashworthiness criteria of the National 

Cooperative Highway Research Program (NCHRP) Report 350. Based on the testing previously 

conducted you asked that we find the device(s) eligible for reimbursement under the Federal-aid 

highway program. Eligibility for reimbursement under the Federal-aid highway program does 

not establish approval or endorsement by the FHWA for any particular purpose or use.

Decision:

The following devices are eligible, with details provided in the referenced letters:

• All breakaway devices previously accepted for Northwest Pipe Company.

Requirements

Roadside safety devices should meet the guidelines contained in the NCHRP Report 350 or the 

American Association of State Highway and Transportation Officials’ Manual for Assessing 

Safety Hardware (MASH). The FHWA Memorandum “Identifying Acceptable Highway Safety 

Features” of July 25, 1997 provides further guidance on crash testing requirements of roadside 

safety 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, Luminaries and Traffic Signals. 

Discussion
2

On June 1, 2011, Trinity Highway Products, LLC purchased the Sign Support business segment 

from Northwest Pipe and has subsequently moved the manufacturing from Houston, TX to the 

Trinity facility located in Fort Worth, TX. Trinity will begin producing product from this facility 

and you requested that the below referenced letters be transferred to Trinity Highway Products, 

LLC. The current letters are:

Letter 

Number

Date Principal product covered by the letter

SS-164 6/18/2010 Poz-Loc 10 inch square slip base system

SS-152 8/23/2007 PSST posts with 30-inch anchors

SS-150R 9/5/2008 Poz-Loc 8 inch square slip base system

SS-130 1/5/2006 Triangular slip base casting 16819

SS-128R 9/5/2008 Poz-Loc slip base casting 28339

SS-126A 11/24/2010 “Performance Post”

SS-126R 9/5/2008 PSST posts

SS-119 2/27/2003 (Correct letter numbering) 

SS-117 11/13/2003 Poz Loc S-Q Post; PozLoc system with extended anchor; PozLoc 

breakaway mailbox system for snow regions

SS-88 8/15/2000 PSST posts

SS-65B 12/3/1997 Poz Loc Slip Base System

SS-65A 6/25/1997 Poz Loc Slip Base System and Poz Loc yielding system

SS-65 9/5/1996 Poz Loc Slip Base System

SS-01A 7/14/1986 Poz Loc anchor system

SS-Ol 5/13/1986 Poz Loc anchor system

These letters detail breakaway sign support systems that have been found crashworthy, and are 

eligible for reimbursement under the Federal-aid highway program. As Trinity Highway 

Products now owns the sign support business segment of Northwest Pipe, these products will 

continue to be eligible if they meet the same specifications, dimensions, material chemistries and 

mechanical properties as the crash tested devices.

Findings

The systems detailed in the letters listed above continue to be eligible for reimbursement and 

should be installed under the range of conditions tested, when such use is acceptable to a 

highway agency.

Please note the following standard provisions that apply to FHWA eligibility letters:

• This finding of eligibility is limited to the crashworthiness characteristics of the systems 

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 system will require 

a new letter.

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

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

significantly different from the version that was crash tested, we reserve the right to 

modify or revoke this letter.
3

• 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 

review, and that it will meet the crashworthiness requirements of the FHWA and the 

NCHRP Report 350. 

• To prevent misunderstanding by others, this letter of eligibility is designated as number 

SS-174 and shall not be reproduced except in full. This letter and the test documentation 

upon which it is based are public information. All such letters and documentation may be 

reviewed at our office upon request. 

• This letter shall not be construed as authorization or consent by the FHWA to use, 

manufacture, or sell any patented system for which the applicant is not the patent holder. 

The finding of eligibility is limited to the crashworthiness characteristics of the candidate 

system, and the FHWA is neither prepared nor required to become involved in issues 

concerning patent law. Patent issues, if any, are to be resolved by the applicant.

Some of the Northwest Pipe devices are patented products and considered proprietary. If 

proprietary systems are specified by a highway agency for use on Federal-aid projects, except 

exempt, non-NHS projects, (a) they must be supplied through competitive bidding with equally 

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

synchronization with the 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

Sincerely yours,

Michael S. Griffith 

Office of Safety Technologies

Office of Safety