October 12, 2004
Refer to: HSA-10/WZ-181
Mr. Peter Speer
Bunzl Extrusion Tacoma Incorporated
3110 70th Avenue East
Tacoma, Washington 98424
Dear Mr. Speer:
Thank you for your letters of September 7, 8, and 9, 2004, requesting Federal Highway Administration (FHWA) acceptance of revisions to your company's T3BTM Type III Barricade as a crashworthy traffic control device for use in work zones on the National Highway System (NHS). You requested that we find the modifications described below acceptable for use with this barricade 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."
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 T3B Barricade is a plastic, lightweight, portable Type III barricade. The T3B 25.4mm x 210mm (1 inch x 8.25) hollow plastic barricade panels are made from a specially formulated polyolefin plastic, and the vertical uprights are 44.5-mm (1.75 inch) square thermoplastic tubing extrusions. The support legs or "skids" are 14 ga, 50.8-mm (2 inch) square perforated galvanized mild steel tubing. One 150-mm (6-inch) tall PSST stub is welded to each support leg, and the vertical uprights are inserted into them. The T3B is available in heights between 1524 mm (60 inches) and 1829 mm (72 inches). Testing of your 2438-mm (8 foot) wide version of this barricade is detailed in the FHWA acceptance letter WZ-39 dated June 29, 2000. The fasteners used were 7.94 mm (5/16") bolts with Nylock nuts and steel washers to attach panels to the uprights.
Your present requests are is to allow the following new designs:
September 7, 2004 letter: 12-foot wide barricades using 1-¾ inch, 12-gage PSST framing
September 8, 2004 letter: Permit the use of a PSST cross bracket for additional stability
September 9, 2004 letter: 12-foot wide barricades using 1-¾ inch plastic X-tube uprights
|Barricade foot||14 gage Qwik-Punch or PSST||2 x 2 x 60" w/ PSST stub or w/splice bracket||12 lb|
|X-Tube upright||Thermoplastic||1-¾ x 1-¾ x 60 in||3.5 lb|
|PSST upright||12 or 14 gage Qwik-Punch or PSST||1-¾ x 1-¾ x 60 in||10.3 lb|
|PSST crossbar||12 or 14 ga PSST (optional)||1-¾ x 1-¾ x 128 in||22 lb|
|T3B 8-inch panels||Thermoplastic||¾ x 8-¼ x 144 inch||11.9 lb|
The connection and mounting hardware will be essentially the same as that which was crash tested. As these substitutions use hardware that has already been shown to be crashworthy, and various combinations have also proven successful, we concur that the present requests should not have a significant affect on the crashworthy performance of the barricade. Therefore, the T3BTM Type III Barricade in the variations detailed above and shown in the enclosed drawings is acceptable for use on the NHS under the range of conditions tested when proposed by a State.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
/Original Signed by/
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety