January 29, 2003
Refer to: HSA-10/WZ-136
Mr.
Henry Ross
United
Rentals Highway Technologies
880
North Addison Road
P.O.
Box 7050
Villa
Park, Illinois 60181-7050
Dear Mr. Ross:
Thank you for your July 24, 2002, letter that you hand delivered to Mr. Nicholas Artimovich of my office on October 23, 2002. In that letter you are requesting Federal Highway Administration (FHWA) acceptance of your company's 8-foot wide Type III barricades using 0.450-inch solid polyethylene plastic panels and X-tube plastic uprights as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying your letter was a summary report of crash testing conducted by E-Tech Testing Services and a CD with photos 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.”
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 “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 frame of the barricade consists of 44.5 mm (1.75 inch) square plastic X-tube uprights. The skids are 2 PPF U-channel posts. The socket for supporting the uprights is a 6-inch long piece of 50.8 mm (2 inch) perforated square steel tube welded to a piece of 7 ga flat steel. The flat steel piece is drilled to accommodate bolts used to attach the socket to the skid. The uprights are simply inserted into the socket. The barricade rails measured 2438 mm long by 203 mm high by 11.4 mm thick (8 feet by 8 inches x 0.14 inch) polyethylene board. The entire barricade (without ballast or lights) weighs 32.8 kg (72.3 pounds.) Each barricade also had two lightweight warning lights mounted to the top of the upright.
Testing
Full-scale automobile testing was conducted on your company's devices. Two stand-alone examples of the device were tested in separate tests, one head-on and one turned at 90 degrees, as permitted in our guidance memoranda. The complete device as tested is shown in Enclosure 1.
The crash test is summarized in the table below:
Test Number |
05-7210-020 |
05-7210-021 |
---|---|---|
Test Article Orientation |
Head on |
90 degrees |
Height to Top Rail |
1570 mm (61.8 inches) |
|
Height to Top of Light |
1860 mm (73.19 inches) |
|
Flags or lights |
Two lightweight lights, one on each upright |
|
Test Article Mass (each) |
32.8 kg (72.3 pounds) plus lights, ballast |
|
Vehicle inertial mass |
813 kg |
813 kg |
Impact Speed |
102.5 km/h |
100.4 km/h |
Velocity Change |
2.2 m/s |
1.6 m/s |
Vehiclecrush |
Denting |
Denting, minor roof crush |
Occupant Compart. Intrusion |
None |
Windshield/roof deformation |
Windshield Damage |
Moderate |
Moderate to severe* |
* In this end-on test the top two rails impacted the windshield causing moderate deformation and cracking. One of the lights hit in such a manner as to snag briefly on the windshield trim and causes a hole through the glass near the roofline. This dime-sized hole did not penetrate the inside metal rim of the windshield mount. Although this nominally violates the FHWA windshield damage criteria for work zone devices, we have carefully considered the implications. This barricade is similar in many respects to other Type III barricades that have been successfully tested. Because of a unique occurrence, it caused a hole in this test.
Damage was limited to moderate to severe cracking of the windshield and minor sheet metal damage to the hood and roof. There did not appear to be a potential for penetration of the occupant compartment. With the exception noted above, the results of the testing met the FHWA requirements and, therefore, the devices 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:
Sincerely yours,
Harry W. Taylor,
Acting Director, Office of Safety Design
Enclosure