Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
October 12, 2005
Refer to: HSA-10/WZ-218
Mr. Mike Harris
Advanced Construction Products
Allied Plastics, Inc.
150 Holly Hill Road
P.O. Box 1010
Twin Lakes, WI 53181
Dear Mr. Harris:
Thank you for your letter of January 31, 2005, and email correspondence of August 22, 2005, requesting the Federal Highway Administration (FHWA) acceptance of your company's Multicade work zone channelizer as a crashworthy traffic control device for use on the National Highway System (NHS). Accompanying your letter was a video of informal crash testing with the Multicade. You requested that we find this device 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 device follows:
The Multicade is a three-sided channelizing device intended to replicate the appearance of a drum. It is a single piece of molded high molecular weight polyethylene plastic with three flat sides that are folded to shape the device and a triangular top piece that folds down to secure the device's shape. The Multicade's wall thickness is a nominal 0.187 inches and a single device weighs 9 pounds.
Because of its unique construction we were uncertain if the Multicade would behave like a Category 1 drum or require full scale testing as a Category 2 device. After considerable discussion we agreed that informal crash testing might be appropriate and should be conducted, with the understanding that the performance may indicate full scale testing could be required. Two stand-alone examples of the device were tested in tandem, one head-on and the next placed ten feet downstream turned at 90 degrees. A Ford Ranger pickup truck was used for these tests, impacting first at 20 mph and the second time at 60 mph. Each Multicade had a truck tire sidewall at the base for ballast. An Empco Light warning light, weighing 3.2 pounds, was attached to each Multicade during these tests. During the 20 mph test the lights remained intact after the impacts, and the Multicades were re-used for the 60 mph test. At 60 mph the Multicades were deformed, but not so badly that they could not be reassembled. Also at 60 mph one of the warning light lenses broke off while the other was slightly cracked.
You also tested a combination of two Multicade units, forming a six-sided "Megacade." No lights were attached, but the vehicle suffered no additional damage of significance after the 60 mph test.
Damage to the vehicle was limited to minor dents and scrapes to the grille and hood. There was no windshield damage, and there did not appear to be any contact with the windshield. The height of the test vehicle's hood was lower than the top of the Multicade; if a warning light and/or lens were to break off and impact the windshield it would be able to reach the windshield as if a smaller test vehicle had been used.
The results of the informal testing met the FHWA requirements and, therefore, 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. Additional testing will be required if the Multicade units are to be used in combination with pipes or barricade rails joining two or more units.
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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