1200 New Jersey Avenue, SE

Washington, D.C. 20590

 

Bob Bielenberg, MSME, EIT 

Research Associate Engineer

Midwest Roadside Safety Facility

527 Nebraska Hall

Lincoln, NE 68588-0529 

Dear Mr. Bielenberg:

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

acceptance of a roadside safety system for use on the National Highway System (NHS).

Name of system: Midwest Guardrail System MGS Median Barrier

Type of system: W-beam median barrier

Test Level: NCHRP Report 350 Test Level 3 

 Testing conducted by: N/A

Task Force 13 Designator: SGM29

Date of request: September 3, 2009 

Date initially acknowledged: September 15, 2009 

Date of completed package: March 22, 2010 

 

You requested that we find this system acceptable for use on the NHS under the provisions of the 

National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended 

Procedures for the Safety Performance Evaluation of Highway Features.” 

Requirements 

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

FHWA Memorandum “Identifying Acceptable Highway Safety Features” of July 25, 1997, 

provides further guidance on crash testing requirements of longitudinal barriers. 

Description

The 31-inch high Midwest Guardrail System (roadside version) was initially found acceptable 

under NCHRP Report 350 in FHWA Acceptance Letter B-133, dated March 1, 2005. Your 

present request is for a median version which consists of the basic MGS guardrail system with a 

second W-beam rail element spaced off of the back side of W6x8.5 or W6x9 steel posts with 

12-inch deep blockouts. 

In Reply Refer To: 

Archived – 

HSSD/B-204 

For 

Research 

and 

Historical 

Purposes 

Only
2

Several existing 31-inch high, guardrail designs have been successfully crash tested in median 

configurations (FHWA Acceptance Letters B-150B and B-162) including systems that did not 

use blockouts in their median barrier configurations. The proposed MGS median barrier system 

is specified with splices at the midspan locations between the posts and uses 12-inch deep 

blockouts, as used on the standard roadside MGS design. Previous testing and analysis of 

guardrail systems has shown that the use of blockouts and placement of the guardrail splices 

away from the posts tends to increase the capacity of guardrail systems and reduce the potential 

for vehicle snag. Therefore, the proposed MGS median barrier system can be expected to have 

improved safety performance as compared to the existing 31-inch high, median W-beam 

guardrail systems.

While the stiffness of the MGS guardrail system would increase due to the use of front and backside W-beam rails, this is not necessarily cause for concern. The MGS was successfully tested 

with a 1⁄4-post spacing which would be much stiffer and have much lower deflections than an 

MGS median system with the additional W-beam rail. Moreover, the length of the MGS post is 

the same as in conventional w-beam roadside and median barrier reducing post embedment. 

Therefore, the additional stiffness of the system is not a concern. 

You recommended placement of the MGS median barrier on either the edge of shoulder or on 

10:1 or flatter median slopes. We concur with these conservative guidelines to ensure acceptable 

safety performance. 

Findings 

Therefore, the system described in the requests above and detailed in the enclosed drawings is 

acceptable for use on the NHS 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 letters of acceptance: 

• This acceptance 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 acceptance 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 our 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 it will meet the crashworthiness requirements of the FHWA and the 

NCHRP Report 350. 

Archived – 

For 

Research 

and 

Historical 

Purposes 

Only
3

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

B-204 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 acceptance 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 acceptance letter 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,

 David A. Nicol, P.E. 

 Director, Office of Safety Design

Office of Safety

FHWA:HSSD:NArtimovich:dp:x61331:4/14/10 

S:DiretoryFolder/HSSD/Artimovich/B204_MGS_Median Barrier(2) 

cc: Reader – HSA, HSSD(Chron File, NArtimovich) 

Archived – 

For 

Research 

and 

Historical 

Purposes 

Only