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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter CC-97A

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U.S. Department of Transportation
Federal Highway Administration

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

March 26, 2008

In Reply Refer To: HSSD/CC-97A

Mr. Chuck Mettler
Engineering Manager
Plastic Safety Systems
2444 Baldwin Road
Cleveland, Ohio 44104

Dear Mr. Mettler:

This letter is in response to your request for the Federal Highway Administration (FHWA) acceptance of a roadside safety device for use on the National Highway System (NHS).

Name of device: Crash Guard Sand Barrel System - Interchangeability
Type of device: Crash Cushion/Impact Attenuator
Test Level: NCHRP Report 350 TL-3
Testing conducted by: Battelle Memorial Institute
Date of request: June 20, 2008, revised November 17, 2008
Date complete information received: November 30, 2008

You requested that we find modules of this device 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” when used to repair installations of sand barrels manufactured by others.

Requirements
Roadside safety devices should meet the guidelines contained in NCHRP Report 350.  The FHWA Memorandum “Action: Identifying Acceptable Highway Safety Features” of July 25, 1997, provides further guidance on crash testing requirements of longitudinal barriers.

Description and Analysis
The FHWA Technical Advisory T5040.20 dated September 22, 1982, states that sand-filled modules of certain manufacturers were considered interchangeable within an array. The focus of the Advisory is repair and maintenance of sand-barrel crash cushions but we do emphasize that new installations should always start out with barrels from the same manufacturer. When faced with repairing a partially damaged attenuator the Advisory says repairs of a Fitch system may be done using Energite barrels, for example.

You asked the FHWA to accept the use of Crash Guard sand barrels as interchangeable with other barrels mentioned in the Advisory. We noted that Crash Guard barrels perform in a different manner than the Energite or Fitch systems in that Crash Guard barrels are designed to break apart at seams rather than allowed to fracture anywhere on the module. Because the barrels perform differently, we asked for additional information on the interaction between the types of barrels.

In the development of the Crash Guard barrels you had them modeled using finite element analysis. You agreed to ask Battelle Memorial Institute to evaluate the crash performance of a mixed array system of the CrashGard and the Energite barrels using finite element analysis. There were many possible barrel arrangements for such a system, however, only selected cases were evaluated. The intent was to select cases considered to be representative of ‘worse’ case scenarios for the mixed array system and these were selected under the direction of the FHWA.

Based on the results of those three cases, it was concluded that, when the CrashGard barrels are used in combination with other FHWA accepted frangible sand barrel systems, the occupant risk and structural performance criteria of NCHRP Report 350 for Test 3-41 would be met. The occupant risk assessment for Case 2 is enclosed for reference.

Findings
Therefore, CrashGuard sand barrels may be used in the same crash cushion installations with frangible barrel systems such as Energite III, Fitch, and Big Sandy sand barrel systems when replacing damaged barrels.

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

 

Sincerely yours,

/* Signature of Mary McDonough */

for David A. Nicol
Director, Office of Safety Design
Office of Safety

Enclosures

Page last modified on January 17, 2013.
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Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000