August 11, 2004
Refer to: HSA-10/WZ-182
Mr. William Korman
3029 Lincoln Avenue
Richmond, Virginia 23228
Dear Mr. Korman:
Thank you for your letter of March 31, 2004, requesting Federal Highway Administration (FHWA) acceptance of your company's Alpolic® 350 sign substrate on Dicke Tool Model No. QFV60 sign stands as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying your letter were drawings of the proposed stand and a discussion of prior crash testing. 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.
The QFV60 stand is a heavy duty extension spring mounted sign support that carries a 48x48 inch square vinyl sign mounted at 58 inches plus. The base consists of rigid aluminum legs 1.25 inches square and 60 inches long attached to the steel bracket holding the extension spring system. The mast is 1.5 inch square aluminum tubing. It was crash tested with three wood flagstaffs in a bracket attached to the top.
Full-scale automobile testing was conducted on the Dicke Tool QVF60 stand with a roll up sign. six meters downstream turned at 90 degrees, as called for in our guidance memoranda. It was the subject of the FHWA acceptance letter WZ-17 dated July 20, 1999. There was no damage to the windshield in the test of this stand.
Your present request is to substitute 48x48 Alpolic® 350 signs for the roll up signs that were crash tested. Crash testing of the QVF60 stand shows that the 5-foot mounting height causes the sign to impact the roof. In the 90-degree test the leading corner of the roll up sign impacted on the roof well beyond the windshield. Because of the good performance of the stand, and the similar good performance of Alpolic® 350 substrates at various heights, we concur in your assertion that signs fabricated of Alpolic® 350 material will perform in an acceptable manner if mounted no less than 5 feet above the ground on the Dicke Tool QVF60 stand. We have contacted Dicke Tool, Inc., and they confirm that they are in agreement with this usage. Therefore, the device 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 FHWA letters of acceptance:
/Original Signed by/
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety