1200 New Jersey Ave., SE

 Washington, D.C. 20590

August 17, 2011

FHWA: HSST: WLongstreet: ms: x60087:8/11/11

File: h://directory folder/HSST/CC109B_X Tenuator Wide Backstop.docx

cc: HSST Will Longstreet 

In Reply Refer To:

HSST/ CC-109B

Mr. Gerrit A. Dyke, P.E.

Barrier Systems, Inc.

3333 Vaca Valley Parkway, Suite 800

Vacaville, CA 95688

Dear Mr. Dyke:

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: X-TENuator and X-TENuator Wide Backstop Extension

Type of system: Backstop Extension for X-TEN and X-TEN Wide Crash Cushions

Test Level: NCHRP Report 350 Test Level 3 (TL-3)

Testing conducted by: Safe Technologies Inc.

Date of request: December 29, 2010

Request Initially acknowledged: January 7, 2011

Task Force 13 designator: SCI23c X-TENuator Backstop Extension; and,

 X-TENuator Wide Backstop Extension

You requested that we find a backstop extension design used in conjunction with your X-TEN 

and X-TEN Wide crash cushions 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.” The original design 

width described in FHWA Acceptance letter CC-109 for your parallel-sided attenuator was 36-

inches (926-millimeters) and the maximum width for your X-TEN Wide described in 

Acceptance letter CC-109A was 60-inches (1525-millimeters) wide.

Requirements

Roadside safety devices should meet the guidelines contained in the NCHRP Report 350 if tested 

prior to December 31, 2010 or the American Association of State Highway and Transportation 

Officials’ Manual for Assessing Safety Hardware (MASH) if tested after that date. The FHWA 

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

further guidance on crash testing requirements of longitudinal barriers.

Decision

The following system design was found acceptable, with details provided below:

• X-TENuator and X-TENuator Wide Backstop Extension
2

Description

The X-TEN and X-TEN Wide systems are both redirective, non-gating crash cushion designed to 

decelerate an errant vehicle to a safe stop when struck end-on or redirect an errant vehicle away 

from roadside or median hazards when impacted along either side. The systems are comprised

of an energy absorbing nose bracket and cover, dual X-Tension impact heads and cables, front 

cable anchors, and W-Beam side panels. The narrow X-TEN uses single posts or double support 

posts with braces, whereas the X-TEN Wide uses only the double row of specially designed 

posts and post braces. Standard W-Beam offset blocks are used to attach the side panels to the 

posts. 

The X-TEN Backstop Extension is intended for use with the X-TEN when hazards wider than 36 

inches (926 millimeters) are encountered or with the X-TEN Wide for hazards greater than 60 

inches (1525 millimeters) in width. By separate correspondence, you indicated that the Backstop 

Extension would be marketed to shield hazards 48 inches, 60 inches, and 72 inches ( 1.2 meters, 

1.5 meters, and1.9 meters ) wide when used behind the narrow, parallel-sided X-TEN, and 86 

inches, 98 inches and 110 inches (2.2 meters, 2.5 meters, and 2.8 meters ) wide hazards when

used with the X-TEN Wide unit. The Backstop Extension (Enclosure 1) uses fabricated steel 

posts (Enclosure 2), variable-sized cross braces (Enclosure 3), and attachment brackets 

(Enclosure 4) in addition to standardized hardware items. 

Crash Testing

Since both the X-TEN and the X-TEN Wide designs were fully crash-tested and accepted for use 

on the NHS by FHWA, only two tests were considered necessary to verify the crashworthiness 

of the X-TEN Backstop Extension. Tests 3-36 and 3-38 were conducted with the Backstop 

Extension installed at its maximum 10-degree angle and connected to the narrow X-TEN design. 

For both tests, the system was attached to a 75-millimeter (3-inch) thick Asphalt Concrete (AC) 

pad over 300 millimeters (12 inches) of a dense graded aggregate with eighty-six (86) 20-

millimeter (3/4-inch) long all thread studs embedded 400 millimeters(16 inches) and epoxied in 

place. Enclosures 5 and 6 summarize the results of these tests.

Findings

The FHWA concurs that the tests you ran were sufficient to verify acceptable crash performance 

under NCHRP Report 350 and that each test met the appropriate evaluation criteria. In your 

letter, you have requested FHWA acceptance of the following:

• The X-TEN Backstop Extension may be considered an NCHRP Report 350 TL-3 design

• The Backstop Extension may be used with the narrow X-TEN to shield hazards up to 72-

inches (1830-millimeters) wide, or with the X-TEN Wide to shield hazards up to 110-

inches (2800-millimeters) wide.

• As with the crash cushions, the Backstop Extension can be installed on an AC pad as 

described above or on a 10-inch (250-millimeter) PCC pad.

• The X-TEN Backstop Extension can be further extended using Thrie-beam barrier and/or 

attached to concrete barrier by using standard transitions that have been accepted for 

attaching “W” profile guardrails to rigid barrier systems.
3

Based on our review of the submitted information, including test reports, the X-TEN Backstop 

Extension described 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 letter includes a Task Force 13 designator to be used when drafting new of revised 

Task Force 13 drawings.

• 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.

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

CC-109B 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.

• The X-TEN Backup Extension is a patented product and considered proprietary. If 

proprietary systems are specified by a highway agency for use on Federal-aid projects, 

except exempt, non-NHS projects, (a) they 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.
4

• 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,

Michael S. Griffith

Director, Office of Safety Technologies

Office of Safety 

Enclosures 
 1200 New Jersey Ave., SE

 Washington, D.C. 20590

August 17, 2011

In Reply Refer To:

HSST/ CC-109B

Mr. Gerrit A. Dyke, P.E.

Barrier Systems, Inc.

3333 Vaca Valley Parkway, Suite 800

Vacaville, CA 95688

Dear Mr. Dyke:

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: X-TENuator and X-TENuator Wide Backstop Extension

Type of system: Backstop Extension for X-TEN and X-TEN Wide Crash Cushions

Test Level: NCHRP Report 350 Test Level 3 (TL-3)

Testing conducted by: Safe Technologies Inc.

Date of request: December 29, 2010

Request Initially acknowledged: January 7, 2011

Task Force 13 designator: SCI23c X-TENuator Backstop Extension; and,

 X-TENuator Wide Backstop Extension

You requested that we find a backstop extension design used in conjunction with your X-TEN 

and X-TEN Wide crash cushions 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.” The original design 

width described in FHWA Acceptance letter CC-109 for your parallel-sided attenuator was 36-

inches (926-millimeters) and the maximum width for your X-TEN Wide described in 

Acceptance letter CC-109A was 60-inches (1525-millimeters) wide.

Requirements

Roadside safety devices should meet the guidelines contained in the NCHRP Report 350 if tested 

prior to December 31, 2010 or the American Association of State Highway and Transportation 

Officials’ Manual for Assessing Safety Hardware (MASH) if tested after that date. The FHWA 

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

further guidance on crash testing requirements of longitudinal barriers.

Decision

The following system design was found acceptable, with details provided below:

• X-TENuator and X-TENuator Wide Backstop Extension
2

Description

The X-TEN and X-TEN Wide systems are both redirective, non-gating crash cushion designed to 

decelerate an errant vehicle to a safe stop when struck end-on or redirect an errant vehicle away 

from roadside or median hazards when impacted along either side. The systems are comprised 

of an energy absorbing nose bracket and cover, dual X-Tension impact heads and cables, front 

cable anchors, and W-Beam side panels. The narrow X-TEN uses single posts or double support 

posts with braces, whereas the X-TEN Wide uses only the double row of specially designed 

posts and post braces. Standard W-Beam offset blocks are used to attach the side panels to the 

posts. 

The X-TEN Backstop Extension is intended for use with the X-TEN when hazards wider than 36 

inches (926 millimeters) are encountered or with the X-TEN Wide for hazards greater than 60 

inches (1525 millimeters) in width. By separate correspondence, you indicated that the Backstop 

Extension would be marketed to shield hazards 48 inches, 60 inches, and 72 inches ( 1.2 meters, 

1.5 meters, and1.9 meters ) wide when used behind the narrow, parallel-sided X-TEN, and 86 

inches, 98 inches and 110 inches (2.2 meters, 2.5 meters, and 2.8 meters ) wide hazards when

used with the X-TEN Wide unit. The Backstop Extension (Enclosure 1) uses fabricated steel 

posts (Enclosure 2), variable-sized cross braces (Enclosure 3), and attachment brackets 

(Enclosure 4) in addition to standardized hardware items. 

Crash Testing

Since both the X-TEN and the X-TEN Wide designs were fully crash-tested and accepted for use 

on the NHS by FHWA, only two tests were considered necessary to verify the crashworthiness 

of the X-TEN Backstop Extension. Tests 3-36 and 3-38 were conducted with the Backstop 

Extension installed at its maximum 10-degree angle and connected to the narrow X-TEN design. 

For both tests, the system was attached to a 75-millimeter (3-inch) thick Asphalt Concrete (AC) 

pad over 300 millimeters (12 inches) of a dense graded aggregate with eighty-six (86) 20-

millimeter (3/4-inch) long all thread studs embedded 400 millimeters(16 inches) and epoxied in 

place. Enclosures 5 and 6 summarize the results of these tests.

Findings

The FHWA concurs that the tests you ran were sufficient to verify acceptable crash performance 

under NCHRP Report 350 and that each test met the appropriate evaluation criteria. In your 

letter, you have requested FHWA acceptance of the following:

• The X-TEN Backstop Extension may be considered an NCHRP Report 350 TL-3 design

• The Backstop Extension may be used with the narrow X-TEN to shield hazards up to 72-

inches (1830-millimeters) wide, or with the X-TEN Wide to shield hazards up to 110-

inches (2800-millimeters) wide.

• As with the crash cushions, the Backstop Extension can be installed on an AC pad as 

described above or on a 10-inch (250-millimeter) PCC pad.

• The X-TEN Backstop Extension can be further extended using Thrie-beam barrier and/or 

attached to concrete barrier by using standard transitions that have been accepted for 

attaching “W” profile guardrails to rigid barrier systems.
3

Based on our review of the submitted information, including test reports, the X-TEN Backstop 

Extension described 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 letter includes a Task Force 13 designator to be used when drafting new of revised 

Task Force 13 drawings.

• 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.

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

CC-109B 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.

• The X-TEN Backup Extension is a patented product and considered proprietary. If 

proprietary systems are specified by a highway agency for use on Federal-aid projects, 

except exempt, non-NHS projects, (a) they 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.
4

• 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,

Michael S. Griffith

Director, Office of Safety Technologies

Office of Safety 

Enclosures