Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
June 15, 2006
Refer to: HSA-10/WZ-238
Mr. Jeffery D. Smith
Work Area Protection Corporation
P.O. Box 4087
2500 Production Drive
St. Charles, Illinois 60174
Dear Mr. Smith :
Thank you for your letter of February 17, 2006, requesting the Federal Highway Administration (FHWA) acceptance of your company's WZS12, WZS12-S, and WZX60-SL portable sign sands as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Your letter included a list of crashworthy signs manufactured by another vendor with whom you have reached agreement to sell under your name. You requested that we find these devices 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.”
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. Our new acceptance process was outlined in our memorandum “FHWA Hardware Acceptance Procedures – Category 2 Work Zone Devices” dated November 11, 2005.
The following sign stand was crash tested by the Texas Transportation Institute and acknowledged as crashworthy in the FHWA acceptance letter WZ-67 dated January 26, 2001.
(Tested sign): A portable work zone sign fabricated with square steel tubing is used to support a 1220 x 1220 mm vinyl roll-up sign panel that is stiffened with 32 mm by 8 mm rectangular cross section fiberglass straps. The mast consists of a 1500 mm long, 32 mm square, 2.5 mm thick steel tube with a 150 mm long, 38 mm square, 2.5 mm thick tube section at the top for sign attachment. Four telescoping legs were fabricated from 25 mm and 30 mm square tubing. The inner legs were 470 mm long while the outer legs were 1168 mm long. The bottom of the roll-up sign was mounted approximately 1.5 m above the ground level. Details of the roll-up sign and stand (in English units) are shown in the enclosed drawing.
You requested acceptance of the WZS60-SL, which is a spring-loaded version of the same stand. You also provided drawings for the model WZS12 stand. This four-legged stand supports a roll-up sign at 305 mm above the pavement. The metal structure of the stand rises no higher than that necessary to secure the bottom of the fiberglass ribs supporting the roll-up sign, as shown on the enclosed drawings. Your model number WZS12S is a spring loaded version of this low stand.
The tested stand contacted the windshield and caused only minor damage and no penetration of the windshield. Therefore, your stand model number WZS60-SL, which is identical to the tested stand except for the use of a spring mechanism at the base, is acceptable for use.
The WZS12 and WZS12-SL stands are both “compact” sign stands under our definition, as detailed in the “Questions and Answers” portion of the FHWA acceptance letter WZ-85, a copy of which is enclosed for your information and use. Compact sign stands supporting
roll-up signs with fiberglass spreaders as detailed in WZ-85 do not require individual crash testing.
The results of the testing of the basic model sign stand met the FHWA requirements. As the manufacturer will fabricate them to the same specifications, the devices described 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.
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
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