1200 New Jersey Ave., SE

 Washington, D.C. 20590

January 27, 2012

FHWA: HSST: Artimovich: sf: x61331:1/25/12

File: s: //directory folder/HSST/Artimovich/ 231_MGS_Stiffness

_Transition Letter.dotx

cc: HSST (NArtimovich; JDewar) 

In Reply Refer To:

HSST/B-231

Scott Rosenbaugh

Research Associate Engineer

Midwest Roadside Safety Facility UNL

2200 Vine Street

130 Whittier Building

Lincoln NE, 68583-0853

Dear Mr. Rosenbaugh:

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

review a roadside safety system for eligibility for reimbursement under the Federal-aid highway 

program. 

Name of system: Transition from steel post MGS to thrie-beam approach

Type of system: W-beam to thrie-beam stiffness transition

Test Level: MASH Test Level 3

Testing conducted by: Midwest Roadside Safety Facility

Task Force 13 Designator: STG03a

Date of request: June 28, 2011

Date initially acknowledged: July 17, 2011

Date of completed package: June 28, 2011

Decision:

The following device is eligible, with details provided in your letter of June 28, 2011, which is 

enclosed as an integral part of this finding:

• Stiffness Transition from steel post MGS with 12-inch deep blockouts to thrie-beam 

approach using asymmetrical “Y.”

Based on a review of crash test results submitted by the manufacturer certifying the device 

described herein meets the crashworthiness criteria of the American Association of State 

Highway and Transportation Officials’ Manual for Assessing Safety Hardware (MASH), the 

device is 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.
2

The FHWA, the Department of Transportation, and the United States Government do not 

endorse products or services and the issuance of a reimbursement eligibility letter is not an 

endorsement of any product or service.

Requirements

Roadside safety devices should meet the guidelines contained in the MASH. 

Description and Crash Testing

Guardrail to bridgerail transitions are designed to gradually increase the stiffness of the semirigid w-beam barrier until connected to the rigid bridge railing. Typically, a single critical 

impact point (CIP) has been evaluated with full-scale crash testing. That CIP is usually located at 

the point where we anticipate the greatest likelihood of vehicle snagging or pocketing near the 

beginning of the rigid bridge railing. Because the stiffness of the barrier transition hardware 

needed to adequately shield the end of the rigid bridge railing is substantial, there is also reason 

to determine if the change in stiffness between the w-beam guardrail and the transition design 

itself is safe. A transition from the MGS with 12-inch deep blockout to a stiffened thrie-beam rail 

using an asymmetrical “Y” transition piece was evaluated in your crash testing. The enclosed 

letter describes the transition design and the two crash tests conducted.

Also enclosed are the test data summary sheets and drawings of the transitions.

Findings

Therefore, the system described and detailed in the attached letter, including the various 

attachment alternatives, is eligible for reimbursement and may be installed under the range of 

conditions tested. 

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

• This letter provides a AASHTO/ARTBA/AGC Task Force 13 designator that should be 

used for the purpose of the creation of a new and/or the update of existing Task Force 13 

drawing for posting on the on-line ‘Guide to Standardized Highway Barrier Hardware’ 

currently referenced in AASHTO Roadside Design Guide. 

• 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 influence the crashworthiness of the system will require a new 

reimbursement eligibility letter.

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

performance reveals safety problems, or that the system is significantly different from the 

version that was crash tested, we reserve the right to modify or revoke this letter.

• 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 the 

same chemistry, mechanical properties, and geometry as that submitted for review, and 

that it will meet the crashworthiness requirements of the Manual for Assessing Safety 

Hardware. 
3

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

B-231 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.

Sincerely yours,

Michael S. Griffith

Director, Office of Safety Technologies

Office of Safety