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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter B-165

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

In Reply Refer To: HSSD/B-165

Malcolm H. Ray, P.E., Ph.D.
186 Staples Hill Road
Canton, ME 04221

Dear Dr. Ray:

This letter is in response to your request for Federal Highway Administration (FHWA) acceptance of roadside safety systems for use on the National Highway System (NHS).

Name of systems: MDS-4 and MDS-5
Type of systems: Steel longitudinal barriers/bridge railings
Test Level: NCHRP Report 350 and MASH-08
Testing conducted by: German Federal Highway Research Institute (BASt)
Date of request: August 1, 2007
Date of follow-up: February 16, 2008

You requested that we find this system acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features”.

Longitudinal barriers should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features". FHWA memorandum “ACTION: Identifying Acceptable Highway Safety Features” of July 25, 1997 provides further guidance on crash testing requirements of longitudinal barriers. You have also chosen to anticipate the adoption of MASH-08, an option that FHWA has offered with the understanding that additional testing may need to be done if changes to the test criteria are made before MASH-08 is formally adopted.

Product description
The MDS-4 and MDS-5 are all-steel safety-shape barriers. The barrier has a unique sliding base assembly that is bolted directly to the bridge deck. The base plate is attached to the deck using four deck anchor bolts that may either be drilled through the deck or epoxyed into the deck depending on the deck design requirements. Six meter long (19.7 ft) 980-mm (38.6 in) high safety-shape panels made of 4 mm (0.1575 inch) thick steel plate are attached to the sliding base and a circular steel tube top rail is mounted to the top of the bridge panels. During an impact, the sliding base is activated in the impact area. This base design allows the panels to push backwards in the impact area dissipating energy while also greatly minimizing the forces experienced by the bridge deck.

The safety-shape panels have dimensions that place it between the conventional dimensions of the New Jersey shape and the F-shape. The barrier is available in two varieties: a 1.240 m (4.1 ft) high system suitable for NCHRP Report 350 Test Level 4 (TL-4) conditions, called the MDS-4, and a 1.595 m (5.2 ft) high system suitable for NCHRP Report 350 Test Level 5 (TL-5) conditions, called the MDS-5. Both versions of the MDS barrier can be used with or without optional noise barriers that are attached to the rear face of the safety barrier. The noise barrier does not contribute to the safety performance of the railing. Design details of MDS-4 and MDS-5 are provided in Enclosure 1.

NCHRP Report 350 requires that in order for longitudinal barriers to meet TL-4 or TL-5 criteria they must successfully pass Tests 10 and 12 and Test 11 may be optional. The NCHRP Report 350 recommends that the results of Test 12 be carefully examined prior to deciding whether Test 11 is needed. Moreover, it notes that satisfactory performance in Test 12 does not assure satisfactory performance in Test 11.

The MDS-4 and MDS-5 barriers were developed in Europe and underwent full crash testing to the European criteria EN 1317. According to the information you provided, all tests were successful (summary of test results is presented in the enclosed tables numbered 2 through 5), however, none of the tests you submitted for our review exactly matched the tests recommended in NCHRP Report 350. In your report you argued that the conducted tests show that: the MDS-4 barrier satisfies both the NCHRP Report 350 and MASH-08 for TL-4 conditions; and that the MDS-5 barrier satisfies both the NCHRP Report 350 and MASH-08 for TL-5 conditions. Specifically, you provided the following table comparing the test conditions to the each of the above standards.

Parameter Report 350 MASH-08 EN1317
Test 4-10/5-10 4-10/5-10 4TB-110
Vehicle Type Passenger Car Passenger Car Passenger Car
Vehicle Mass (kg) 820 1100 900
Vehicle c.g. height (mm) 550   490
Impact Velocity (km/hr) 100 100 100
Impact Angle (deg) 20 25 20
Impact Severity (kJ) 37,007 75,797 40,617
Test 4-12 4-12 TB-51
Vehicle Type Single Unit Truck Single Unit Truck Bus
Vehicle Mass (kg) 8,000 10,000 13,000
Vehicle c.g. height (mm) 1,250 1,700 1,400
Impact Velocity (km/hr) 80 90 70
Impact Angle (deg) 15 15 20
Impact Severity (kJ) 132,320 209,334 287,478
Test 5-12 5-12 TB-81
Vehicle Type Tractor Trailer Tractor Trailer Tractor Trailer
Vehicle Mass (kg) 36,000 36,000 38,000
Vehicle c.g. height (mm) Not specified 1,850 1,900
Impact Velocity (km/hr) 80 80 65
Impact Angle (deg) 15 15 20
Impact Severity (kJ) 595,438 595,438 724,562

Based on the comparison of the test conditions, we concur that the results of EN 1317 tests TB-11 (passenger car) and TB-51 (bus) conducted on MDS-4 barrier are indicative of the performance in Tests 4-10 and 4-12 of the NCHRP Report 350 and MASH-08. Likewise, it seems reasonable to accept the results of EN 1317 Tests TB-11 and TB-81 conducted on MDS-5 barrier as indicative of the performance of the barrier in Tests 5-10 and 5-12 of the NCHRP Report 350 and MASH-08.

However, none of the tests conducted on MDS-4 and MDS-5 barriers are indicative of the performance of the barrier with the pick-up truck in Tests 4-11 and 5-11. We concur that the shape of the barrier face is within the range of previously tested safety shapes. However, in your initial submission the plates forming the face of the barrier were of thinner sheet steel. We expressed our concern that rigid elements of the pick-up truck’s suspension or wheel assembly could deform that steel and result in a hard snag. We recommended an increase in thickness of those steel plates to 4 mm and you agreed.

Based on the results of the conducted tests and their comparability to the tests recommended by NCHRP 350 and MASH-08, we consider the MDS-4 and MDS-5 barriers acceptable for use on the NHS as NCHRP 350 MASH-08 TL-4 and TL-5 barriers, respectively, without a pickup truck test. The above systems may be used at all appropriate locations on the NHS when selected by the contracting authority, subject to the provisions of Title 23, Code of Federal Regulations, Section 635.411, as they pertain to proprietary products.

Please note that this acceptance is for MDS-4 and MDS-5 barriers proper and currently there are no transitions to this barrier accepted to NCHRP 350 criteria. Until crashworthy transitions can be designed and tested, an approach consisting of a w- or thrie-beam transition to a concrete safety shape may be used, with the MDS barriers anchored to the end of the concrete section Also, this acceptance is based on the reported crash performance of the barrier and is not meant to address its installation, maintenance or repair characteristics.

Because it is a steel product, the MDS-4 and MDS-5 barriers are subject to Section 635.410 (Buy America) of Title 23, U.S. Code of Federal Regulations, and cannot be permanently incorporated into any federally funded project unless it is made in the U.S. from U.S. steel.

Because MDS-4 and MDS-5 barriers are currently made in Europe and detailed drawings in standard U.S. dimensions and nomenclature are not currently available, you will be expected to certify to any users that the barrier provided for installation is identical to that which was tested, particularly in regard to material specifications and anchorage details.

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


Sincerely yours,

Signature of David A. Nicol

David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety


See the B-165 PDF to view the following:

Title 23, Code of Federal Regulations

§ 635.410 Buy America requirements.

(a) The provisions of this section shall prevail and be given precedence over any requirements of this subpart which are contrary to this section. However, nothing in this section shall be construed to be contrary to the requirements of §635.409(a) of this subpart.

(b) No Federal-aid highway construction project is to be authorized for advertisement or otherwise authorized to proceed unless at least one of the following requirements is met:

(1) The project either: (i) Includes no permanently incorporated steel or iron materials, or (ii) if steel or iron materials are to be used, all manufacturing processes, including application of a coating, for these materials must occur in the United States. Coating includes all processes which protect or enhance the value of the material to which the coating is applied.

(2) The State has standard contract provisions that require the use of domestic materials and products, including steel and iron materials, to the same or greater extent as the provisions set forth in this section.

(3) The State elects to include alternate bid provisions for foreign and domestic steel and iron materials which comply with the following requirements. Any procedure for obtaining alternate bids based on furnishing foreign steel and iron materials which is acceptable to the Division Administrator may be used. The contract provisions must (i) require all bidders to submit a bid based on furnishing domestic steel and iron materials, and (ii) clearly state that the contract will be awarded to the bidder who submits the lowest total bid based on furnishing domestic steel and iron materials unless such total bid exceeds the lowest total bid based on furnishing foreign steel and iron materials by more than 25 percent.

(4) When steel and iron materials are used in a project, the requirements of this section do not prevent a minimal use of foreign steel and iron materials, if the cost of such materials used does not exceed one-tenth of one percent (0.1 percent) of the total contract cost or $2,500, whichever is greater. For purposes of this paragraph, the cost is that shown to be the value of the steel and iron products as they are delivered to the project.

(c)(1) A State may request a waiver of the provisions of this section if;

(i) The application of those provisions would be inconsistent with the public interest; or

(ii) Steel and iron materials/products are not produced in the United States in sufficient and reasonably available quantities which are of a satisfactory quality.

(2) A request for waiver, accompanied by supporting information, must be submitted in writing to the Regional Federal Highway Administrator (RFHWA) through the FHWA Division Administrator. A request must be submitted sufficiently in advance of the need for the waiver in order to allow time for proper review and action on the request. The RFHWA will have approval authority on the request.

(3) Requests for waivers may be made for specific projects, or for certain materials or products in specific geographic areas, or for combinations of both, depending on the circumstances.

(4) The denial of the request by the RFHWA may be appealed by the State to the Federal Highway Administrator (Administrator), whose action on the request shall be considered administratively final.

(5) A request for a waiver which involves nationwide public interest or availability issues or more than one FHWA region may be submitted by the RFHWA to the Administrator for action.

(6) A request for waiver and an appeal from a denial of a request must include facts and justification to support the granting of the waiver. The FHWA response to a request or appeal will be in writing and made available to the public upon request. Any request for a nationwide waiver and FHWA's action on such a request may be published in the Federal Register for public comment.

(7) In determining whether the waivers described in paragraph (c)(1) of this section will be granted, the FHWA will consider all appropriate factors including, but not limited to, cost, administrative burden, and delay that would be imposed if the provision were not waived.

(d) Standard State and Federal-aid contract procedures may be used to assure compliance with the requirements of this section.

635.411 Material or product selection.

(a) Federal funds shall not participate, directly or indirectly, in payment for any premium or royalty on any patented or proprietary material, specification, or process specifically set forth in the plans and specifications for a project, unless:

(1) Such patented or proprietary item is purchased or obtained through competitive bidding with equally suitable unpatented items; or

(2) The State transportation department certifies either that such patented or proprietary item is essential for synchronization with existing highway facilities, or that no equally suitable alternate exists; or

(3) Such patented or proprietary item is used for research or for a distinctive type of construction on relatively short sections of road for experimental purposes.

(b) When there is available for purchase more than one nonpatented, nonproprietary material, semifinished or finished article or product that will fulfill the requirements for an item of work of a project and these available materials or products are judged to be of satisfactory quality and equally acceptable on the basis of engineering analysis and the anticipated prices for the related item(s) of work are estimated to be approximately the same, the PS&E for the project shall either contain or include by reference the specifications for each such material or product that is considered acceptable for incorporation in the work. If the State transportation department wishes to substitute some other acceptable material or product for the material or product designated by the successful bidder or bid as the lowest alternate, and such substitution results in an increase in costs, there will not be Federal-aid participation in any increase in costs.

(c) A State transportation department may require a specific material or product when there are other acceptable materials and products, when such specific choice is approved by the Division Administrator as being in the public interest. When the Division Administrator's approval is not obtained, the item will be nonparticipating unless bidding procedures are used that establish the unit price of each acceptable alternative. In this case Federal-aid participation will be based on the lowest price so established.

(d) Appendix A sets forth the FHWA requirements regarding (1) the specification of alternative types of culvert pipes, and (2) the number and types of such alternatives which must be set forth in the specifications for various types of drainage installations.

(e) Reference in specifications and on plans to single trade name materials will not be approved on Federal-aid contracts.

(f) In the case of a design-build project, the following requirements apply: Federal funds shall not participate, directly or indirectly, in payment for any premium or royalty on any patented or proprietary material, specification, or process specifically set forth in the Request for Proposals document unless the conditions of paragraph (a) of this section are applicable.

[41 FR 36204, Aug. 27, 1976, as amended at 67 FR 75926, Dec. 10, 2002]

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