Federal Highway Administration
1200 New Jersey Ave. S.E.
Washington, D.C. 20590
January 24, 2008
In Reply Refer To:
Mr. Stephen T. Zimar
1430 Sullivan Street
Elmira, NY 14901-1698
Dear Mr. Zimar:
In your November 15, 2007, letter you requested modifications to previously issued Federal Highway Administration (FHWA) acceptance letters of your company’s crashworthy sign stands using various sign substrates for use in work zones on the National Highway System (NHS). You requested acceptance of your stand models in the X-600 Series with a sign mounting height of 7 feet above grade 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”. This taller height would be identified as the X-840 Series.
The X-600 Series are currently accepted at a mounting height of 5 feet and for use with various substrates including roll-up, corrugated plastics, aluminum composites, 0.80 and 0.10 inch aluminum, and 5/8 inch plywood (see WZ-59, WZ-78A, WZ-87B, and WZ-103A). To achieve the 7 feet mounting height above grade the following changes are proposed: subtract 16 inches of aluminum tubing from the top mast, and add a third middle mast section of aluminum tube 46 inches long; replace the two vertical steel coil springs below the mast sections with vertical fiberglass springs. Adding two feet to the mast height created the need for increased stability of the sign stand. Each leg was lengthened by adding 12 inches of aluminum tubing. The aluminum bottom mast, which incorporates your previously accepted frangible coupling would remain in place within the bottom mast section, and would not be altered in any way.
Based on the crashworthy characteristics of this sign stand as previously tested, the requested additional height will not pose an increased risk to the occupant compartment or cause excessive vehicle velocity change. Therefore, we acknowledge your X-840 Series sign stands with sign mounting heights at seven feet above grade are acceptable for use on the NHS when selected by the contracting authority.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
David A. Nicol
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