Federal Highway Administration |
400 Seventh St., S.W. Washington, D.C. 20590 |
March 4, 2005
Refer to: HSA-10/WZ-199
Mr. Kenneth H. Williamson
Personal Safety First
P.O. Box 9026
Memphis, Tennessee 38190-9026
Dear Mr. Williamson:
Thank you for your letter of November 4, 2004, requesting Federal Highway Administration (FHWA) acceptance of your company's Rubbersand ballast as a crashworthy element of A-Frame Type I and Type II barricades for use in work zones on the National Highway System (NHS). Accompanying your letter were reports of crash testing conducted by Tri State Testing Services, Inc., and a DVD of the tests. You requested that we find these devices acceptable for use on the NHS under the provisions of the National Cooperative Highway Research Program Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features."
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 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.
Testing
Full-scale automobile testing was conducted on Rubbersand ballasts placed in Type II A-Frame barricades. Two stand-alone barricades 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. Each barricade was weighted with two Rubbersand ballasts weighing 9.5 pounds each, one placed each end of the barricade. As seen in the enclosed drawing for reference, the Rubbersand ballast conforms to the void in the A-Frame of the barricade.
The polypropylene foam/plastic - recycled plastic A-Frame legs of each barricade measured 40 3/8 inches tall, 23 3/8 inches wide at the base, and 1 15/16 inches thick. Each barricade rail was 7 ¾ inches wide, 1 ¾ inches thick, and 6 feet, 8 inches long.
The tests are summarized in the table below.
Test Number |
LO-32907-A |
|
---|---|---|
Barricade Orientation |
Head-on |
90 degrees |
Weight of Barricade |
Approx. 28 pounds |
|
Weight of Ballast |
Two 9 pound Rubbersands |
Two 9 pound Rubbersands |
Flags? Lights? |
None |
None |
Mass of Test Vehicle |
1800 pounds |
|
Impact Speed |
64 mph |
Not recorded |
Velocity Change |
N/A |
N/A |
Extent of contact |
Bumper, Grille |
Bumper, grille, windshield |
Windshield Damage |
No contact |
Few small spots of plastic |
Other notes |
No cracking or deformation of the windshield occurred. |
Findings
Damage was limited to breakage to the grille of the test vehicle, and minor abrasions to the windshield. None of the Rubbersand devices came near the windshield as they remained at bumper level or lower. Portions of the vehicle's grille were knocked loose and impacted the windshield, leaving small contact marks on the surface while causing no cracking.
The results of the testing met the FHWA requirements and, therefore, the devices described in the various requests 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. The Rubbersand barricade ballast may be used on any acceptable A-Frame or "Parade-style" barricade when placed no higher than approximately 14 inches above the ground (as measured to the bottom of the Rubbersand weight.)
Please note the following standard provisions that apply to the FHWA letters of acceptance:
Sincerely yours,
/Original Signed by/
~for~
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety
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