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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter

Safety Eligibility Letter WZ-104

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U.S. Department
of Transportation
Federal Highway
400 Seventh St., S.W.
Washington, D.C. 20590

Refer To: HSA-10/WZ-104

Mr. Donald D. Diecks
PMG Limited Lobo
POBox 552
Chagrin Falls, OH 44022-0552

Dear Mr. Diecks:

Thank you for your letter of October 24 requesting Federal Highway Administration (FHWA) acceptance of your company’s Sentinel Type III Plastic Panel Barricade as a crashworthy traffic control device for use in work zones on the National Highway System (NHS). Accompanying your letter was a report of crash testing conducted by E-Tech Testing Services and a video of the tests. You requested that we find these devices acceptable for use on the National Highway System under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.” Mr. Nicholas Artimovich of my office gave you an initial response via fax on November 5, 2001, and asked for additional information which you subsequently provided.

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 were those lightweight devices which could be self-certified by the vendor, Category II devices were other lightweight devices which needed individual crash testing, Category III devices were barriers and other fixed or massive devices also needing crash testing, and Category IV devices were trailer mounted lighted signs, arrow panels, etc. 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 device follows:

The Sentinel Type III barricade is a compact lightweight device featuring blow molded high density polyethylene upper and lower supports and hollow extruded plastic panels. The upper and lower supports are joined together with a simple slip-fit connection. The 210 mm high by 1219 mm long barricade panels are made from a specially formulated polyolefin plastic and surfaced with reflective sheeting. Each of the three panels is secured to the uprights with four 9.5 mm diameter by 76.2 mm long ASTM A307 hex bolts and nuts with plain washers front and back. The mass of each test article was 13.4 kg. Each was placed on a flat, clean, and dry asphalt surface with three 15.9 kg sandbags placed on the lower support legs of each barricade for ballast. The complete devices as tested are shown in the enclosed drawings for reference.

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 crash test is summarized in the table below:

Test Number 38-8707-001 , NCHRP Test 3-71
Test Article Sentinel Type III Plastic Panel Barricade
Height to Top of Barricade 1524 mm (60 inches)
Flags or lights none
Test Article Mass (each) 13.4 kg
Vehicle Inertial Mass 824 kg
Impact Speed, Head-on 101.8 km/hr
Impact Speed, 90 Deg. 97.7 km/hr
Velocity Change, Head-on 1.14 m/sec
Velocity Change, 90 deg. 1.14 m/sec
Vehicle crush Slight hood damage
Occupant Compart. Intrusion None
Windshield Damage None - only glancing contact with first test article

When struck the upper portions of the barricades came out of the base sections and were knocked ahead of the vehicle. Damage was limited to dents and scrapes in the hood. There did not appear to be any potential for passenger compartment intrusion. The results of the testing met the FHWA requirements and, therefore, the devices described above and shown in the enclosed drawings for reference are acceptable for use on the NHS under the range of conditions tested, when proposed by a State.

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

  Sincerely yours,


Michael L. Halladay
Acting Program Manager, Safety


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Page last modified on June 24, 2011
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