MGS Midwest Guardrail System

W-Beam Barrier for the Future

Existing W-Beam barriers were developed many years ago when the vehicle fleet was different than it is today. These existing W-Beam barriers measure 27 5/8'' to the top of the rail. When crash tested with today's higher center of gravity vehicles, many results have not been successful.

The differences between the MGS Barrier and the older W-Beam barrier is:

• The MGS top of rail height is 31'' rather than 27 5/8''.
• The MGS blockout is 12'' rather than 8''.
• The MGS W-Beam rail splices occur mid span between posts rather than at the post.

In 2001-2002, the Midwest States Pooled Fund Program funded by 11 States recognized the need for a new generic strong post W-Beam barrier that would be compatible with the newer higher center of gravity vehicles crash tested under NCHRP 350 Test Level 3 conditions. The result was the MGS Barrier.

MGS (Midwest Guardrail System) W-Beam Barrier - Benefits

• The MGS Barrier is totally generic, no patented parts meaning all guardrail producers can supply it. Uses the same 12'' W-Beam rail section in use today.
• The MGS Barrier was tested with (1'-6 3/4'' & 3'-1 1/2'') reduced post spacing.
• The MGS Barrier was tested 6'' behind a 6'' curb.
• The MGS Barrier was tested with flare rates as sharp as 7:1 (with pickup and small car) compared to the 14:1 (Test Level 3) recommended in the AASHTO Roadside Design Guide.
• The MGS Barrier was tested at a 32'' rail height with the 1800 pound small car.
• The MGS Barrier has its own transition. Both the 2000P (4400 lb. pickup) and the 820C (1800 lb. small car) tests were passed with the asymmetrical Thrie-Beam section. This is the first time any W-to Thrie transition has successfully passed.
• As part of the rewrite of NCHRP 350 [NCHRP Project 22-14(2)], the MGS barrier was successfully tested with both the 5000 pound quad cab and 5000 pound 3/4 ton pickup trucks.
• As part of the rewrite of NCHRP 350 [NCHRP Project 22-14(2)], the MGS barrier was successfully tested with the 2425 pound small car at the 32'' rail height.
• The MGS Barrier has a greater construction tolerance. The MGS tested to 32'' and having all of the components of the system tested at 27 5/8'' allows the States to both set a construction tolerance for the rail system and to overlay the road without adjusting the system.
• There is ongoing funding for the MGS barrier. The system will be tested on a slope, with the posts set on the break line of a 2:1 slope. It will also be tested in a long span application with 3 missing posts.
• The MGS Barrier has both tangent and flared terminals tested in the MGS configuration as an option.
• The MGS barrier offers many variables to accommodate the real world site conditions.

The SKT and FLEAT were successfully crash tested in the MGS configuration.

Comparison Charts: Improved MGS Terminals and Current Terminals

More Information

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• MGS Guardrail
• MGS Newsletter written by the Engineers at the Midwest Roadside Safety Facility (MwRSF) (PDF file, opens in separate window)
• MGS Terminals (PowerPoint File, 7.7 MB, opens in separate window)
• MGS Barrier Report (PDF file, opens in separate window)
• MGS Barrier: March 1, 2005 (PDF file, opens in separate window)
• SKT & FLEAT MGS Terminals: March 8, 2005 (PDF file, opens in separate window)