Ronald K. Faller, Ph.D., P.E. 

 Research Assistant Professor 

 Midwest Roadside Safety Facility 

 P.O. Box 880601 

 Lincoln, NE 68588-0601 

 Dear Dr. Faller: 

In your letter dated January 24, 2005, you requested formal Federal Highway Administration 

acceptance of a non-proprietary strong-post W-beam guardrail, named the Midwest Guardrail 

System (MGS), as an NCHRP Report 350 test level 3 (TL-3) longitudinal barrier. In support of 

this request, you sent copies of your September 2004 report prepared under the direction of the 

Midwest States’ Regional Pooled Fund Program, entitled “Development of the Midwest 

Guardrail System (MGS) for Standard and Reduced Post Spacing and in Combination with 

Curbs” and video and digital films of the tests you conducted. 

The MGS barrier, as shown in Enclosure 1, consists of standard 12-gauge W-beam sections 

installed with the top of the rail set at a nominal height of 787 mm (31 inches). Note that this 

drawing depicts the rail element at its recommended maximum height rather than at its nominal

height. It is mounted on standard W152x13.4 steel posts that are 1829-mm (6-feet) long and set 

on 1905-mm (75-inch) centers. To obtain the additional rail height, each post is raised 

approximately 100 cm (4 inches), resulting in slightly less embedment than the posts in a 

standard W-beam installation. The rail is offset from these posts with 152-mm wide x 305-mm 

deep x 356-mm long (6-inch x 12-inch x 14-inch) wood offset blocks. For the test installation, 

these blocks were made from two separate blocks screwed together to obtain the design depth, 

but it is anticipated that production blocks will be a single piece. Routed or toenailed blocks may 

also be used to prevent block rotation over time, but neither feature was used in your tests. 

Finally, the rail splices are located at mid-span between adjacent posts rather than at each post as 

in a traditional W-beam installation. 

The MGS barrier was tested successfully with the 820-kg car and the 2000-kg pickup truck in its 

standard configuration, behind a 152-mm (6-inch) AASHTO Type B curb with the pickup truck 

(Enclosure 2), and with a reduced post spacing of 476 mm (18.75 inches). Summaries of each 

test are shown on Enclosure 3. I noted that the initial test with the 820-kg car was run 

with the top of rail set at 813 mm (32 inches) thus establishing the maximum recommended 

height of the MGS to preclude wheel snagging by the small car. Since standard W-beam 

remains acceptable at a nominal top rail height of 686 mm (27 inches), the recommended 

minimum height of the MGS barrier is likewise 686 mm (27 inches). I noted also that in the test 

with the curb, the face of the MGS barrier was set 178 mm (7 inches) from the toe of the curb. 

In a separate discussion, you advised that the face of the rail could be moved forward over the 

toe of the curb, but advised against moving it further back without additional testing. 

400 Seventh St., S.W. 

Washington, D.C. 20590

In Reply Refer To: HSA-10/B-133 March 1, 2005 
2

Using a BARRIER VII analysis calibrated from the standard and 1⁄4 post spacing tests; you 

estimated the design deflection of the MGS barrier with a 953-mm (37.5-inch) or half-post 

spacing. From your testing and analysis, you recommended that the minimum distances at which 

the face of an MGS installation be placed from the face of a rigid obstacle (e.g., bridge pier or 

overhead sign support) be 1.25 m (49 inches), 1.12 m (44 inches), and 0.90 m (35 inches) for 

standard, 1⁄2, and 1⁄4 post spacings, respectively. These offsets are based on the “working width” 

deflections seen in the crash tests/analysis and include some degree of pickup truck penetration 

beyond the vertical plane of the barrier’s dynamic deflection. As with all traffic barriers, larger 

offset distances would be required to shield similar features from vehicles with higher centers of 

gravity, such as single-unit trucks or as buses, because of the relatively high roll angles seen with 

these vehicles in rigid and semi-rigid barrier tests of similar height. 

Based on staff review of the information you submitted, I agree that the tested designs satisfy 

NCHRP Report 350 evaluation criteria for a longitudinal barrier at TL-3 and that each of these 

designs may be used on the National Highway System. Based on your discussions with and 

recommendations to Mr. Richard Powers of my staff, I also agree the MGS system, in any of the 

configurations described herein, may be used with standard 1829-mm (6-foot) long timber posts 

in lieu of the tested steel post design. 

Sincerely yours, 

 /Original Signed by Richard Powers/ 

 

 ~for~ 

John R. Baxter, P.E. 

 Director, Office of Safety Design 

 Office of Safety 

3 Enclosures 




72

0.000 sec 0.088 sec 0.147 sec 0.189 sec 

! Test Number . . . . . . . . . . . . . . . . . . . NPG-1! Date . . . . . . . . . . . . . . . . . . . . . . . . . 6/29/01! Appurtenance .................. Midwest Guardrail System

Key Elements . . . . . . . . . . . . . . increased mounting height, blockout depth, 

and bolt slot length, mid-span splices

! Total Length . . . . . . . . . . . . . . . . . . . 55.25 m! Steel W-beam

Thickness . . . . . . . . . . . . . . . . . 2.66 mmTop Mounting Height . . . . . . . . 813 mm

Bolt Slot Length . . . . . . . . . . . . 102 mm

! Steel Posts

Post Nos. 3 - 27 . . . . . . . . . . . . . W152 x 13.4 by 1,829-mm long

Spacing . . . . . . . . . . . . . . . . . . . 1,905 mm

! Wood Posts

Post Nos. 1 - 2, 28 - 29 (BCT) . 140 mm x 190 mm by 1,080-mm long

! Wood Spacer Blocks

Post Nos. 3 - 27 . . . . . . . . . . . . . 152 mm x 305 mm by 356-mm long

! Soil Type . . . . . . . . . . . . . . . . . . . . . Grading B - AASHTO M 147-65 (1990)! Vehicle Model . . . . . . . . . . . . . . . . . 1994 Geo Metro

Curb . . . . . . . . . . . . . . . . . . . . . 746 kgTest Inertial . . . . . . . . . . . . . . . . 812 kgGross Static . . . . . . . . . . . . . . . . 887 kg

! Vehicle Speed

Impact . . . . . . . . . . . . . . . . . . . . 102.9 km/h

Exit (resultant) . . . . . . . . . . . . . 92.3 km/h

! Vehicle Angle

Impact (trajectory) . . . . . . . . . . . . . . Exit (trajectory) . . . . . . . . . . . . . . . . 

! Vehicle Stability . . . . . . . . . . . . . . . . . . . ! Occupant Ridedown Deceleration (10 mse

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Occupant Impact Velocity

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Vehicle Damage . . . . . . . . . . . . . . . . . . . 

TAD31 . . . . . . . . . . . . . . . . . . . . . . . . 

SAE32 . . . . . . . . . . . . . . . . . . . . . . . . 

! Vehicle Stopping Distance . . . . . . . . . . . ! Barrier Damage . . . . . . . . . . . . . . . . . . . . ! Maximum Rail Deflections

Permanent Set . . . . . . . . . . . . . . . . . 

Dynamic . . . . . . . . . . . . . . . . . . . . . . 

! Working Width . . . . . . . . . . . . . . . . . . . . 

Figure 37. Summary of Test Results and Sequential Photographs, Test NPG-1
141

0.000 sec 0.101 sec 0.190 sec 0.323 sec 

! Test Number . . . . . . . . . . . . . . . . . . . NPG-4! Date . . . . . . . . . . . . . . . . . . . . . . . . . 6/14/02! Appurtenance .................. Midwest Guardrail System

Key Elements . . . . . . . . . . . . . . increased mounting height, blockout depth,

and foundation tube length, mid-span splices

! Total Length . . . . . . . . . . . . . . . . . . . 55.25 m! Steel W-beam

Thickness . . . . . . . . . . . . . . . . . 2.66 mmTop Mounting Height . . . . . . . . 787 mm

Bolt Slot Length . . . . . . . . . . . . 64 mm

! Steel Posts

Post Nos. 3 - 27 . . . . . . . . . . . . . W152 x 13.4 by 1,829-mm long

Spacing . . . . . . . . . . . . . . . . . . . 1,905 mm

! Wood Posts

Post Nos. 1 - 2, 28 - 29 (BCT) . 140 mm x 190 mm by 1,080-mm long

! Steel Foundation Tube Length . . . . . 1,829 mm! Wood Spacer Blocks

Post Nos. 3 - 27 . . . . . . . . . . . . . 152 mm x 305 mm by 356-mm long

! Soil Type . . . . . . . . . . . . . . . . . . . . . Grading B - AASHTO M 147-65 (1990)! Vehicle Model . . . . . . . . . . . . . . . . . 1995 GMC 2500 3⁄4-ton pickup

Curb . . . . . . . . . . . . . . . . . . . . . 1,913 kg

Test Inertial . . . . . . . . . . . . . . . . 1,986 kgGross Static . . . . . . . . . . . . . . . . 1,986 kg

! Vehicle Speed

Impact . . . . . . . . . . . . . . . . . . . . 98.1 km/hExit (resultant) . . . . . . . . . . . . . 55.1 km/h

! Vehicle Angle

Impact (trajectory) . . . . . . . . . . . . . . Exit (trajectory) . . . . . . . . . . . . . . . . 

! Vehicle Stability . . . . . . . . . . . . . . . . . . . ! Occupant Ridedown Deceleration (10 mse

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Occupant Impact Velocity

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Vehicle Damage . . . . . . . . . . . . . . . . . . . 

TAD31 . . . . . . . . . . . . . . . . . . . . . . . . 

SAE32 . . . . . . . . . . . . . . . . . . . . . . . . 

! Vehicle Stopping Distance . . . . . . . . . . . ! Barrier Damage . . . . . . . . . . . . . . . . . . . . ! Maximum Deflections

Permanent Set . . . . . . . . . . . . . . . . . 

Dynamic . . . . . . . . . . . . . . . . . . . . . . 

! Working Width . . . . . . . . . . . . . . . . . . . . 

Figure 87. Summary of Test Results and Sequential Photographs, Test NPG-4
166

0.000 sec 0.080 sec 0.151 sec 0.237 sec 

! Test Number . . . . . . . . . . . . . . . . . . . NPG-5! Date . . . . . . . . . . . . . . . . . . . . . . . . . 9/4/02! Appurtenance .................. Midwest Guardrail System with Curb

Key Elements . . . . . . . . . . . . . . increased mounting height, blockout depth,

and foundation tube length, mid-spansplices, and curb

! Total Length . . . . . . . . . . . . . . . . . . . 55.25 m! Steel W-beam

Thickness . . . . . . . . . . . . . . . . . 2.66 mmTop Mounting Height . . . . . . . . 787 mm

Bolt Slot Length . . . . . . . . . . . . 64 mm

! Steel Posts

Post Nos. 3 - 27 . . . . . . . . . . . . . W152 x 13.4 by 1,829-mm long

Spacing . . . . . . . . . . . . . . . . . . . 1,905 mm

! Wood Posts

Post Nos. 1 - 2, 28 - 29 (BCT) . 140 mm x 190 mm by 1,080-mm long

! Steel Foundation Tube Length . . . . . 1,829 mm! Wood Spacer Blocks

Post Nos. 3 - 27 . . . . . . . . . . . . . 152 mm x 305 mm by 356-mm long

! Curb . . . . . . . . . . . . . . . . . . . . . . . . . 152-mm tall Type B mounted 152 mm

. . in front of guardrail face

! Soil Type . . . . . . . . . . . . . . . . . . . . . Grading B - AASHTO M 147-65 (1990)! Vehicle Model . . . . . . . . . . . . . . . . . 1997 Chevrolet C2500 3⁄4-ton pickup

Curb . . . . . . . . . . . . . . . . . . . . . 1,813 kg

Test Inertial . . . . . . . . . . . . . . . . 1,991 kgGross Static . . . . . . . . . . . . . . . . 1,991 kg

! Vehicle Speed

Impact . . . . . . . . . . . . . . . . . . . . . . . Exit (resultant) . . . . . . . . . . . . . . . . . 

! Vehicle Angle

Impact (trajectory) . . . . . . . . . . . . . . Exit (trajectory) . . . . . . . . . . . . . . . . 

! Vehicle Stability . . . . . . . . . . . . . . . . . . . ! Occupant Ridedown Deceleration (10 mse

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Occupant Impact Velocity

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Vehicle Damage . . . . . . . . . . . . . . . . . . . 

TAD31 . . . . . . . . . . . . . . . . . . . . . . . . 

SAE32 . . . . . . . . . . . . . . . . . . . . . . . . 

! Vehicle Stopping Distance . . . . . . . . . . . ! Barrier Damage . . . . . . . . . . . . . . . . . . . . ! Maximum Deflections

Permanent Set . . . . . . . . . . . . . . . . . 

Dynamic . . . . . . . . . . . . . . . . . . . . . . 

! Working Width . . . . . . . . . . . . . . . . . . . . 

Figure 105. Summary of Test Results and Sequential Photographs, Test NPG-5
191

0.000 sec 0.077 sec 0.164 sec 0.295 sec 

! Test Number . . . . . . . . . . . . . . . . . . . NPG-6! Date . . . . . . . . . . . . . . . . . . . . . . . . . 10/18/02! Appurtenance .................. Midwest Guardrail System with reduced

post spacing

Key Elements . . . . . . . . . . . . . . reduced post spacing, increased mounting

height, blockout depth, and foundationtube length

! Total Length . . . . . . . . . . . . . . . . . . . 55.25 m! Steel W-beam

Thickness . . . . . . . . . . . . . . . . . 2.66 mmTop Mounting Height . . . . . . . . 787 mm

Bolt Slot Length . . . . . . . . . . . . 64 mm

! Steel Posts

Post Nos. 3 - 59 . . . . . . . . . . . . . W152 x 13.4 by 1,829-mm long

! Steel Post Spacing

Post Nos. 3 - 8, 54 - 59 . . . . . . . 1,905 mm

Post Nos. 9 - 10, 52 - 53 . . . . . . 953 mmPost Nos. 11 - 51 . . . . . . . . . . . . 476 mm

! Wood Posts

Post Nos. 1 -2, 60 - 61 (BCT) . . 140 mm x 190 mm by 1,080-mm long

! Steel Foundation Tube Length . . . . . 1,829 mm! Wood Spacer Blocks

Post Nos. 3 - 59 . . . . . . . . . . . . . 152 mm x 305 mm by 356-mm long

! Soil Type . . . . . . . . . . . . . . . . . . . . . Grading B - AASHTO M 147-65 (1990)! Vehicle Model . . . . . . . . . . . . . . . . . 1997 GMC C2500 3⁄4-ton pickup

Curb . . . . . . . . . . . . . . . . . . . . . 1,971 kg

Test Inertial . . . . . . . . . . . . . . . . 2,001 kgGross Static . . . . . . . . . . . . . . . . 2,001 kg

! Vehicle Speed

Impact . . . . . . . . . . . . . . . . . . . . . . . Exit (resultant) . . . . . . . . . . . . . . . . . 

! Vehicle Angle

Impact (trajectory) . . . . . . . . . . . . . . Exit (trajectory) . . . . . . . . . . . . . . . . 

! Vehicle Stability . . . . . . . . . . . . . . . . . . . ! Occupant Ridedown Deceleration (10 mse

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Occupant Impact Velocity

Longitudinal . . . . . . . . . . . . . . . . . . . Lateral (not required) . . . . . . . . . . . . 

! Vehicle Damage . . . . . . . . . . . . . . . . . . . 

TAD31 . . . . . . . . . . . . . . . . . . . . . . . . 

SAE32 . . . . . . . . . . . . . . . . . . . . . . . . 

! Vehicle Stopping Distance . . . . . . . . . . . ! Barrier Damage . . . . . . . . . . . . . . . . . . . . ! Maximum Deflections

Permanent Set . . . . . . . . . . . . . . . . . 

Dynamic . . . . . . . . . . . . . . . . . . . . . . 

! Working Width . . . . . . . . . . . . . . . . . . . . 

Figure 124. Summary of Test Results and Sequential Photographs, Test NPG-6