April 29, 1996
Refer to: HNG-14/SS-59A
Mr. Mark Granger
Chicago Heights Steel
211 E. Main
P.O. Box 129
Chicago heights, Illinois 60411
Dear Mr. Granger:
This is in response to you March 30 letter to Mr. Nicholas Artimovich of the Geometric and Safety Design Group. You requested the Federal Highway Administration's acceptance of a modification to your company's "Safety Splice" breakaway system for u-channel sign supports. You provided background and supporting information for your request. The unmodified version of the Safety Splice system was found acceptable for up to three 5.9 kg/m u-channel posts within a 2.1-meter span by our Geometric and Roadside Design Acceptance Letter SS-59 dated March 7.
The proposed modification would replace the un-threaded spacers used with each of the two connecting bolts with a single bar of steel, drilled and tapped with threaded holes 4 inches (102 mm) apart. The spacer bar will be 3/8-inch (9.5 mm) thick, as were the individual spacers used in the crash tests. A Drawing of the Safety Splice with the bar spacer is enclosed.
We concur that the spacer bar will cause no significant change to the breakaway performance of the Safety Splice system and that no additional crash testing will be required. Therefore, your company's breakaway Safety Splice system with the spacer bar will be acceptable for use on the Nation Highway System when requested by a Sate. All other conditions in our March 7 letter remain in effect.
We understand that you are applying for a patent on the Safety Splice with the spacer bar. If a patent is granted, then the design will be considered proprietary. To be used in Federal-aid highway projects, except exempt non-NHS projects, proprietary products: (a) must be supplies through competitive bidding with equally suitable unpatented items; (b) the highway agency must certify that they are essential for synchronization with existing highway facilities or that no equally suitable alternate exists; or (c) they must be used for research or for a distinctive type of construction on relatively short sections of road for experimental purposes. Our regulations concerning proprietary products are contained in Title 23, Code of Federal Regulations, Section 635.411, a copy of which is enclosed.
Seppo I. Sillan, Acting Chief
Federal Aid and Design Division
Supplement to Geometric and Safety Design Acceptance Letter SS-59