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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter WZ-281B

Safety Eligibility Letter WZ-281B

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

April 18, 2016

In Reply Refer To:

Mr. Troy Tapley
MDI Worldwide
38271 W. Twelve Mile Road
Farmington Hills, Michigan  48331

Dear Mr.Tapley:

This letter is in response to your May 5, 2015 request for the Federal Highway Administration (FHWA) to review a roadside safety device, hardware, or system for eligibility for reimbursement under the Federal-aid highway program. This FHWA letter of eligibility is assigned FHWA control number WZ-281B and is valid until a subsequent letter is issued by FHWA that expressly references this device.


The following devices are eligible, with details provided in the form which is attached as an integral part of this letter:

Scope of this Letter

To be found eligible for Federal-aid funding, modified roadside safety devices should meet the crash test and evaluation criteria contained in the National Cooperative Highway Research Program (NCHRP) Report 350. However, the FHWA, the Department of Transportation, and the United States Government do not regulate the manufacture of roadside safety devices. Eligibility for reimbursement under the Federal-aid highway program does not establish approval, certification or endorsement of the device for any particular purpose or use. 

This letter is not a determination by the FHWA, the Department of Transportation, or the United States Government that a vehicle crash involving the device will result in any particular outcome, nor is it a guarantee of the in-service performance of this device. Proper manufacturing, installation, and maintenance are required in order for this device to function as tested.

This finding of eligibility is limited to the crashworthiness of the system and does not cover other structural features, nor conformity with the Manual on Uniform Traffic Control Devices.

Eligibility for Reimbursement

FHWA previously issued an eligibility letter for the roadside safety system described in your pending request. Your pending request now identifies a modification to that roadside safety system.

The original roadside safety device information is provided here:

Name of system: 50TRI tripod sign stand
Type of system: Work Zone Traffic Control Device
Date of original request:

April 30, 2009

Date of original FHWA eligibility letter: July 1, 2009
FHWA Control number


The pending modification(s) consists of the following changes:

  1. The 30TRI legs are constructed of round steel tubing 1.00 in × .065 in [25mm × 1.5mm] in diameter instead of square steel tubing 1.25 in × 1.25 in × 0.065 in [30 mm × 30 mm × 1.6 mm].
  2. The 30TRI overall mass is 12 lbs. [5.4 kg] compared to a mass of 16 lbs. [7.3 kg].
  3. Use with the following comparable 48" × 48" (16 - sq. ft) and smaller sign substrates:
    1. 0.375" [9.5mm] and 0.500" [12.7mm] thick plywood signs
    2. 0.080" [2mm], 0.100" [2.5mm], and 0.125" [3mm] thick solid aluminum
    3. 0.080" [2mm] and 0.125" [3mm] aluminum laminates such as: Alpolic, Dibond, Reynolite or similar substrates
    4. 0.400" [10mm] to 0.625" [16mm] corrugated plastics

FHWA concurs with the recommendation of the accredited crash testing laboratory as stated within the attached form.

Full Description of the Eligible Device

The device and supporting documentation, including reports of the crash tests or other testing done, videos of any crash testing, and/or drawings of the device, are described in the attached form.


If a manufacturer makes any modification to any of their roadside safety hardware that has an existing eligibility letter from FHWA, the manufacturer must notify FHWA of such modification with a request for continued eligibility for reimbursement.  The notice of all modifications to a device must be accompanied by:

FHWA's determination of continued eligibility for the modified hardware will be based on whether the modified hardware will continue to meet the relevant crash test criteria.

You are expected to supply potential users with sufficient information on design, installation and maintenance requirements to ensure proper performance.

You are expected to certify to potential users that the hardware furnished has the same chemistry, mechanical properties, and geometry as that submitted for review, and that it will meet the test and evaluation criteria of the NCHRP Report 350.

Issuance of this letter does not convey property rights of any sort or any exclusive privilege. This letter is based on the premise that information and reports submitted by you are accurate and correct. We reserve the right to modify or revoke this letter if: (1) there are any inaccuracies in the information submitted in support of your request for this letter, (2) the qualification testing was flawed, (3) in-service performance or other information reveals safety problems, (4) the system is significantly different from the version that was crash tested, or (5) any other information indicates that the letter was issued in error or otherwise does not reflect full and complete information about the crashworthiness of the system.

Standard Provisions


Sincerely yours,

Signature Michael S. Griffith

Michael S. Griffith
Director, Office of Safety Technologies
Office of Safety


Page last modified on May 24, 2016
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