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U.S. Department of Transportation

Federal Highway Administration

400 Seventh St., S.W.
Washington, D.C. 20590

December 6, 2005

Refer to: HSA-10/WZ-212

Mr. Brent Short, President
Flex Safe, Inc.
60 Catherine Street
Boston, Massachusetts 02131

Dear Mr. Short:

Thank you for your letter of April 28, 2005, requesting the Federal Highway Administration (FHWA) acceptance of your company's Flex Safe Barricades as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying your letter were reports of crash testing conducted by E-TECH Testing Services and video of the tests. You requested that we find these devices 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 FHWA guidance on crash testing of work zone traffic control devices is contained in two memoranda. The first, dated July 25, 1997, titled "INFORMATION: Identifying Acceptable Highway Safety Features," established four categories of work zone devices: Category I devices are those lightweight devices which are to be self-certified by the vendor, Category II devices are other lightweight devices which need individual crash testing but with reduced instrumentation, Category III devices are barriers and other fixed or heavy devices also needing crash testing with normal instrumentation, and Category IV devices are trailer mounted lighted signs, arrow panels, etc. for which crash testing requirements have not yet been established. The second guidance memorandum was issued on August 28, 1998, and is titled "INFORMATION: Crash Tested Work Zone Traffic Control Devices." This later memorandum lists devices that are acceptable under Categories I, II, and III.

A brief description of the devices follows:

The Flex-Safe Barricade consists of a carbon steel tubing linkage that unfolds into an A-frame like barricade. It supports a nylon "messaging" banner which extends lengthwise across the top of the barricade at a nominal height of 900 mm. The barricade linkage is made from 22 mm diameter 22 ga (0.760 mm) SAE08 welded carbon steel tubing which is powder coat
painted. The linkage is fastened together with 1/4" – 20 (6.4 mm) SAEJ1061 ASTM 788 zinc-plated carbon steel fasteners and extend out to a nominal width of 2.2 m. Stamped carbon steel spreader hinges (galvanized 3.17 mm x 19.05 mm x 457.2 mm) at each end of the linkage lock the barricade in the extended position. A set of folding auxiliary "guide rails" comprised of 19 mm schedule 40 PVC pipe are snap fitted to the top and bottom of the barricade to complete the assembly. Each barricade has a mass of 8.2 kg.

Full-scale automobile testing was conducted on your company's devices. Two stand-alone examples of the device were tested in tandem, one head-on and the next placed six meters downstream turned at 90 degrees, as called for in our guidance memoranda.

The tests are summarized in the table below.

NCHRP Report 350 Test 3-71

Test Number


Sign Stand Tested



Weight of Tested Stand

8.2 kg

8.2 kg

Mounting heights

900 mm

900 mm

Flags? Lights?



Mass of Test Vehicle

838 kg

Impact Speed

103.2 km/hr

101.1 km/hr

Velocity Change

0.58 m/sec

Extent of contact

Debris rode up windshield

Debris rode up windshield

Windshield Damage



Other notes

No damage to vehicle

No damage to vehicle

Upon impact the barricade broke up harmlessly with portions going up the windshield and passing over the car without causing any damage.

The results of the testing met the FHWA requirements and, therefore, the devices described in the various requests above and detailed in the enclosed drawings are acceptable for use on the NHS under the range of conditions tested, when proposed by a State. Additional evaluation and/or crash testing will be required should you wish the FHWA acceptance for your barricades when they are linked together to form a longitudinal channelizing barricade. We expect that the safety performance will be satisfactory from the standpoint of the occupants of the errant vehicle, but the deflection and "whipping" effect of unsecured barrier ends.

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

Sincerely yours,

/original signed by /

John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety


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