July 15, 2004
Refer to: HSA-10/WZ-187
Mr. Dennis C. Hipskind
Three Rivers Barricade and Equipment Company
3330 Taylor Street
Fort Wayne, Indiana 46802
Dear Mr. Hipskind
Thank you for your letter of April 7, 2004, requesting Federal Highway Administration (FHWA) acceptance of your company's "KMAC" Portable Sign Stands as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying your letter were reports of crash testing conducted by E-TECH Testing Services and 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."
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 devices follows:
The main upright supports for the signs are made of nominal 102mm x 102mm inch dimensional pressure treated wood cross braced with nominal 51 mm x 102 mm dimensional lumber having 16 and 20 penny nailed connections. The signs are attached to 2438 mm long 2.98 kg/m steel u-channel supports which are in turn bolted to the uprights such that the bottom edge of the signs are a nominal 2134 mm above ground level. The signs are bolted to the u-channels with four 7.94 mm GD 2 fasteners that pass through drilled holes in the supports. The u-channels for the aluminum signs are attached with five bolts, nuts, and washers on each side and those for the plywood sign use four on each side. Each sign is equipped with two 2.3 kg warning lights and the base of the test articles are ballasted with six 16 kg sand bags.
Full-scale automobile testing was conducted on the devices. Two stand-alone examples of the device were tested in separate vehicle runs, one head-on and one turned to 90 degrees, as called for in our guidance memoranda.
The tests are summarized in the table below.
|Sign Stand Tested||Diamond Sign(1219 x 1219 mm)2.54 mm Aluminum Perpendicular Orientation||Rectangular Sign(1219 x 1524 mm, vertical)12.7 mm PlywoodHead-on Orientation|
|Weight of Tested Stand||95.5 kg||111.1 kg?|
|Mounting heights||2134 mm||2134 mm|
|Flags? Lights?||Yes, two lights||Yes, two lights|
|Mass of Test Vehicle||819 kg|
|Impact Speed||100.4 km/hr||98.3 km/hr|
|Velocity Change (OIV)||2.4 m/s||2.6 m/s|
|Extent of contact||Dents in bumper, grill, and hood||Dents in bumper, grill, and hood|
|Windshield Damage||No windshield contact||No windshield contact|
OIV: Occupant Impact Velocity (max allowable is 5.0 m/s).
Damage was limited to dents in the bumper, grill, and hood areas of the test vehicles. The results of the 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.
You also asked that this stand be accepted with the following variations:
1. Any sign substrate weighing up to and including 1.40 pounds per square foot (i.e., 0.080, 0.100 solid aluminum, Safetycore, ½ inch thick CDX or MDO plywood)
2. Any size sign up to and including 20 square feet.
3. With or without one or two standard warning lights weighing up to and including 5.069 pounds each.
These variations will be acceptable for use on the NHS when requested by a State, with the restriction that the mounting height of 2134 mm from the groundline to the bottom of the sign be maintained.
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