December 18, 2002

Refer to: HSA-10/WZ-130

Mr. David Stoudt
Sign Up Corporation
P.O. Box 14624
Portland, Oregon  97293

Dear Mr. Stoudt:

Thank you for your letter of June 14, 2002, requesting Federal Highway Administration (FHWA) acceptance of your company=s X-CELL 48 HDL tall portable sign stands as crashworthy traffic control devices for use in work zones on the National Highway System (NHS).  Accompanying your letter was a report of crash testing conducted by E-Tech Testing Services and a video of the tests. 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.”  You provided additional information at our request via a facsimile message on December 12, 2002.

Introduction

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 AINFORMATION: 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 devices follows:

The X-CELL 48 HDL Sign Stand is a portable sign system featuring a spring loaded upright support and a 1219 mm x 2 mm thick diamond shaped aluminum sign. The sign stand has four legs made of 25.4 mm square 2 mm wall tubing. The tips of the legs are rubber capped and form a 2235 mm by 1321 mm base pattern. The material specification is ASTM A500/A513 Grade A for all ERW (electronic resistance welded) steel square tubing used in the sign support.  Each leg is attached to an “X-CELL” assembly which spring loads the sign support upright.

The X-CELL assembly in turn supports a sign mounting stem “socket” made from 31.8 mm square 2.4 mm wall tube.  A 25.4 mm square 2 mm wall steel tubing “center mast” is locked into the stem by a spring detent pin.  A 19.1 mm square 1.6 mm wall steel tubing “upper mast” is locked into the stem by a spring detent pin.  The sign is mounted to the mast with two sliding “rigid sign clamps.”  Each clamp has two 9.5 mm carriage bolts with wing nuts used to clamp down on the sign corner.  The clamps are secured in position on the mast with a thumbscrew.  The lower rigid sign clamp supports the bottom of the sign 1626 mm above ground level.  A flag holder, made of two 20 gage steel plates formed and spot welded together, completes the top of the mast.  Three 457 mm square vinyl fabric flags with wooden dowels were attached to the top of the support.

Testing

Full-scale automobile testing was conducted on your company=s devices.  Two stand-alone examples of the device were tested in tandem, one head-on and the next placed six meters downstream turned at 90 degrees, as called for in our guidance memoranda.  The complete device as tested is shown in Enclosure 1.  The crash test is summarized in the table below:

Findings

Damage was nonexistent in this impact as the mast separated from the base and the sign rotated over the vehicle in both impacts.  Velocity changes were well below the maximum and within the “desirable” range.  The results of the testing met the FHWA requirements and, therefore, the portable sign stand described above and shown in the enclosed drawings for reference 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:

• Our acceptance is limited to the crashworthiness characteristics of the devices and does not cover their structural features, nor conformity with the Manual on Uniform Traffic Control Devices.
  
  
• Any changes that may adversely influence the crashworthiness of the device will require a new acceptance letter.
  
  
• Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the device being marketed is significantly different from the version that was crash tested, it reserves the right to modify or revoke its acceptance.
  
  
• You will be expected to supply potential users with sufficient information on design and installation requirements to ensure proper performance.
  
  
• You will be expected to certify to potential users that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for acceptance, and that they will meet the crashworthiness requirements of FHWA and NCHRP Report 350.
  
  
• To prevent misunderstanding by others, this letter of acceptance, designated as number WZ-130 shall not be reproduced except in full. This letter, and the test documentation upon which this letter is based, is public information.  All such letters and documentation may be reviewed at our office upon request.
  
  
• The X-CELL 48 HDL Sign Stand may include patented components and if so are considered "proprietary." The use of proprietary work zone traffic control devices in Federal-aid projects is generally of a temporary nature. They are selected by the contractor for use as needed and removed upon completion of the project. Under such conditions they can be presumed to meet requirement "a" given below for the use of proprietary products on Federal-aid projects. On the other hand, if proprietary devices are specified for use on Federal-aid projects, except exempt, non-NHS projects, they: (a) must be supplied 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 alternative 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.
  

Sincerely yours,

Harry W. Taylor
Acting Director, Office of Safety Design       

Enclosure