1200 New Jersey Ave., S.E. 

Washington, DC 20590 March 26, 2008 

In Reply Refer To: HSSD/B-150A 

Mr. Andrew Artar 

Vice President Sales and Marketing 

Gregory Highway Products 

4100 13th Street, SW 

Canton, OH 44710 

Dear Mr. Artar: 

This is in response to your letter of November 1, 2007, requesting the Federal Highway 

Administration’s (FHWA) acceptance of your company’s single- and dual-face w-beam Gregory 

Mini Spacer (GMS) Guardrail Systems as a test level 3 (TL-3) device for use on the National 

Highway System (NHS). Accompanying your letter were reports of crash testing conducted by 

Southwest Research Institute. You requested that we find this device acceptable for use on the 

NHS under the provisions of the forthcoming American Association of State Highway and 

Transportation Officials Manual on Assessing Safety Hardware-2008 (MASH08), which is 

expected to supersede Report 350 in the near future. 

Introduction 

The FHWA guidance on crash testing of roadside safety hardware is contained in a 

memorandum dated July 25, 1997, titled “INFORMATION: Identifying Acceptable Highway 

Safety Features” and recognizes National Cooperative Highway Research Program (NCHRP) 

Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway 

Features” as the current crash test guidance. The Gregory Highway Products has chosen to 

anticipate the adoption of MASH08 by testing with the 2270P vehicle, an option that FHWA has 

offered with the understanding that testing may need to be done over if changes to the test 

criteria are made before MASH08 is formally adopted. 

The GMS system was found acceptable under NCHRP Report 350 criteria in our FHWA 

acceptance letter B-150 dated October 27, 2006. Your present request is for MASH08 

acceptance of the same barrier system, described as follows: 

The GMS system consists of 12-gauge steel W-beam panels mounted directly onto standard, 

unmodified 6-foot long W6 x 8.5 steel posts with no offset blocks or backup plates, spaced at 

6 feet 3 inches and with a top-of-rail height of either 31 inches or 27 5/8 inches. The rail was 

attached to each post using a 5/16-inch diameter standard hex head bolt incorporated into a 

proprietary releasable fastener called a “GMS” that enables conventional guardrail and posts to 

perform without the need for offset blocks. 
2

The two test summary sheets using the 2270P vehicle, one each for the 27 5/8 inch height 

(Test GMS-4) at TL-2 and one for the same mounting height (Test GMS-6) at TL-3, are enclosed 

for reference. Testing with the 820C vehicle on the 31 inch dual-face w-beam barrier having two 

splices at every other post had been conducted under the initial testing (Test GMS-2) and is 

considered a “worst case scenario” as it used a lighter vehicle than called for in MASH08 

potentially subjecting vehicle occupants to higher impact forces, especially since there were two 

rail connections at each post contacted by the vehicle. 

Testing 

Full-scale automobile and pickup testing has been conducted on the GMS barrier. Tests GMS-1 

and GMS-2 supported FHWA acceptance letter B-150. Tests GMS-4 and GMS-6 were 

conducted to support the present request. The GMS-4 was intended to be a TL-3 test but a 

testing malfunction resulted in inadequate impact speed and re-run as GMS-6. Selected barrier 

and crash test details, including dynamic deflection, are summarized in the following table. 

 

Test # Test Designation Barrier Height* Barrier Deflection** 

GMS-1 MASH08 TL-3 / 3-11 31 inches. Single faced. 2.92 ft 

GMS-2 Report 350 TL-3 / 3-10 31 inches Dual faced 2.20 ft 

GMS-4 MASH08 TL-2 / 2-11 27-5/8 inches Single faced 2.25 ft 

GMS-6 MASH08 TL-3 / 3-11 27-5/8 inches Single faced 4.33 ft 

* Height to top of rail. 

** Maximum dynamic deflection. Our current criteria sets the “design deflection distance” at 

the maximum dynamic deflection recorded in Report 350 test 3-11. From the crash testing you 

performed and your analysis (a method that agrees with a tuned Barrier VII analysis), you came 

up with recommended Report 350 test 3-11 (2000P) deflection criteria. You recommend that the 

minimum distances at which the face of a GMS 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 (6 ft 3 inch), 1/2, and 1/4 post spacing, 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 buses, because 

of the relatively high roll angles seen with these vehicles in rigid and semi-rigid barrier tests of 

similar height. 

Findings

As noted in the enclosed test data summary sheets the test vehicles were smoothly redirected and 

met occupant impact force and occupant compartment deformation criteria. Therefore, the 

system described above is acceptable for use on the NHS under the range of conditions tested, 

when such use is acceptable to the contracting authority. You also requested the following be 

included in this acceptance letter: 

 

• The GMS-WB system may be installed with top-of-rail height between 27 and 32 inches. 

• The GMS-WB may be installed with splices at or between posts. 

• The GMS-WB may be installed with Modified G4(1S) W6 x 8.5 steel posts or with 

G4(2W) nominal 6 x 8 inch rectangular or G4(RW) nominal 7 inch diameter round 

timber posts. 

• The GMS spacer called a “Mini Spacer” may be used on any non-proprietary strong or 

weak post w-beam barrier length-of-need with or without the use of a spacer block, and 

such usage will not change the test level of the barrier on which it is used. 
3

We concur in these variations for both single face and dual face installations. 

 

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

• This acceptance is limited to the crashworthiness characteristics of the devices. 

• Any changes that may adversely influence the crashworthiness of the device 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 device being marketed is 

significantly different from the version that was crash tested we reserve the right to 

modify or revoke its 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 they will meet the crashworthiness requirements of the FHWA and 

MASH08. 

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

B-150A and shall not be reproduced except in full. This letter and the test documentation 

upon which this letter is based are public information. All such letters and 

documentation may be reviewed at our office upon request. 

• The Gregory Mini Spacer is a patented product and considered proprietary. If proprietary 

devices are specified by a highway agency for use on Federal-aid projects, except 

exempt, non-NHS projects, they: (a) must be supplied through competitive bidding with 

equally suitable unpatented items; (b) the highway agency must certify that they are 

essential for synchronization with the existing highway facilities or that no equally 

suitable alternative exists; or (c) they must be used for research or for a distinctive type of 

construction on relatively short sections of road for experimental purposes. Our 

regulations concerning proprietary products are contained in Title 23, Code of Federal 

Regulations, Section 635.411. 

• This acceptance letter shall not be construed as authorization or consent by the FHWA to 

use, manufacture, or sell any patented device for which the applicant is not the patent 

holder. The acceptance letter is limited to the crashworthiness characteristics of the 

candidate device, 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 

2 Enclosures 

FHWA:HSSD:NArtimovich:tb:x61331:3/19/08 

File: s://directory folder/nartimovich/B150A_GMS_MASH08fin.doc 

cc: HSSD (Reader, HSA; Chron File, HSSD; N.Artimovich, HSSD 

 M.Bloschock, HSSD; MMcDonough, HSSD) 
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20

Table 4.1 – Summary of Test Results and Conditions 

General Information Impact Conditions Test Article Deflec

Test Agency .....................Southwest Research Institute Speed (km/hr) ..........86 Dynamic ...........

Test Number ....................GMS-4 Angle (degrees)........25.3 Permanent.........

Test Date..........................08/14/2007 Exit Conditions Vehicle Damage 

Test Category...................2-11 Speed (km/hr) ..........49 (calculated) Exterior 

Test Article Angle (degrees)........12.8 CDC .................

Type ................................Longitudinal Barrier Occupant Risk Values VDS .................

Installation Length ...........57.15 m (187.5 ft) Impact Velocity (m/s) Interior 

Nom. Barrier Height ........702 mm (27-5/8 in) x-direction .........4.9 OCDI ................

Type of Primary Barrier...Modified G4-1S Longitudinal Barrier y-direction .........-4.2 Max. Deform. (m

Soil Stable, Dry – “Standard” Soil Ridedown Accelerations (g’s) Test Vehicle x-direction .........-7.1 

Type ................................1⁄2 Ton Quad Cab Pickup y-direction .........4.7 Designation ......................2270P Post Impact Vehicular Behavior (limited to events <1.000 secon

Model...............................2002 Dodge Ram 1500 Quad Cab Maximum Roll Angle (degrees) ................-14.3 @ 0.541 sec. 

Mass (kg) .........................2200 Maximum Pitch Angle (degrees) ...............-9.0 @ 0.755 sec. Inertial Mass(kg)..............2200 Maximum Yaw Angle (degrees)................44.0 @ 0.561 sec. Dummy Mass (kg) ...........NA Gross Static Mass (kg).....2200 
23

Table 4.1 – Summary of Test Results and Conditions 

General Information Impact Conditions Test Article Deflec

Test Agency .....................Southwest Research Institute Speed (km/hr) ..........105.7 Dynamic ...........

Test Number ....................GMS-6 Angle (degrees)........24.6 Permanent.........

Test Date..........................09/24/2007 Exit Conditions Vehicle Damage 

Test Category...................3-11 Speed (km/hr) ..........72 (calculated) Exterior 

Test Article Angle (degrees)........20 CDC .................

Type ................................Longitudinal Barrier Occupant Risk Values VDS .................

Installation Length ...........57.15 m (187.5 ft) Impact Velocity (m/s) Interior 

Nom. Barrier Height ........702 mm (27-5/8 in) x-direction .........4.0 OCDI ................

Type of Primary Barrier...Modified G4-1S Longitudinal Barrier y-direction .........-4.6 Max. Deform. (m

Soil Stable, Dry – “Standard” Soil Ridedown Accelerations (g’s) Test Vehicle x-direction .........-8.7 

Type ................................1⁄2 Ton Quad Cab Pickup y-direction .........8.1 Designation ......................2270P Post Impact Vehicular Behavior (limited to events <1.000 secon

Model...............................2002 Dodge Ram 1500 Quad Cab Maximum Roll Angle (degrees) ................-46.3 @ 0.871 sec. 

Mass (kg) .........................2200 Maximum Pitch Angle (degrees) ...............-17.2 @ 0.850 sec. 

Inertial Mass(kg)..............2200 Maximum Yaw Angle (degrees)................52.1 @ 1.446 sec. 

Dummy Mass (kg) ...........NA Gross Static Mass (kg).....2200