April 1, 2003
Refer to: HSA-10/WZ-148
Mr. Larry Leahy
P.O. Box 135
Auburn, Illinois 62615
Dear Mr. Leahy:
This is in response to your letter of January 14 requesting Federal Highway Administration (FHWA) acceptance of a modification to your company's Type III Barricades as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying your letter were drawings of the modified barricade and a discussion of the changes. 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 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.
Our letter to you WZ-51, dated September 8, 2000, summarized a number acceptable Type III barricades framed with perforated square steel tube elements. One style of barricade uses gusset plates attached to either side of the skid. The barricade's “uprights” are secured between these two gusset plates The X-Cessories Squared Shear Bolt Model TL132 employs rectangular gusset plates having two horizontal backing lugs, one on either side of a single 3/8 inch cross bolt in order to secure the plate to the bottom skid. The TBB-3 model uses a trapezoidal plate with two 3/8 inch cross bolts for the same purpose. You requested acceptance of the TBB-3, modified to the single bolt, double lug connection to the skid (as on the TL132 model.) The revised shear pin barricade bracket is designated TBB3-C.
We concur that this minor change to the gusset plate connection will not significantly affect the performance of the barricade and, therefore, the barricade connection described above and detailed 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 FHWA letters of acceptance:
Acting Director, Office of Safety Design
Office of Safety