Refer to: HSA-10/WZ-132
Mr. Scott Behm
Three D Traffic Works, Inc.
430 North Varney Street
Burbank, California 91502
Dear Mr. Behm:
Thank you for your June 23, 2003, letter to Mr. Nicholas Artimovich requesting Federal Highway Administration (FHWA) acceptance of your company's Type III barricade Model TD2400. Accompanying your letter were the crash test report and videos produced by E-Tech Testing Services. You requested that we find this all-plastic barricade acceptable under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features for use in work zones on the National Highway System (NHS).
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.
The Three D Traffic Works TD2400 Series Type III Barricade is a FHWA Category II work zone traffic control device. The barricade is described and dimensioned in the enclosure "TD2400 Series Type III Barricade Product Information Sheet." It is an all plastic, lightweight, portable barricade made from a specially formulated polypropylene plastic with UV stabilizers and cold weather package. The barricade panel construction is detailed in the enclosure "TD2400 Series Type III Barricade Panel Product Information Sheet."
Panels for crashworthy barricades are available in 1219, 1524, 1829, and 2438, mm (4, 5, 6, and 8 foot) lengths. A 2438 mm (8 foot) wide barricade panel was selected for testing. The barricade plastic upright support legs are referred to as Tuff-1TM uprights and are specially designed with an extrusion pattern which yields additional strength. These plastic uprights are a nominal 1600 mm (5 feet, 4 inches) in length and 44.5 mm (1.75 inches) square. The uprights are supported by injection molded "EZ Foot" bases with nominal 1524 mm (5 feet) length and 305 mm (1 foot) nominal height and width.
The test articles were equipped with the Flex-O-Lite signal Sundowner TM warning lights at the top of the each upright. The warning light design is shown in the enclosed "Flex-O-Lite Sundowner Warning Light Product Information Sheet." The warning lights were outfitted with one battery each and the barricade bases were ballasted with two 16 kg (35 pounds) sand bags each, positioned on the diagonal.
Full-scale automobile testing was conducted on your company's devices. Two stand-alone examples of the devices 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 tests are summarized in the table below.
|Test Number||NCHRP 350 Test 3-71|
|Barricade Orientation||Head-on||90 degrees|
|Weight of Tested Stand||20.4 kg (45 pounds)|
|Weight of Sand Ballast||Two 16 kg bags (70 pounds of sand, total)|
|Mounting heights||1600 mm (63 inches) to top of top rail|
|Flags? Lights?||Two Flex-O-Lite Sundowner warning lights|
|Mass of Test Vehicle||821 kg (1808 pounds)|
|Impact Speed||98.3 km/hr||96.4 km/hr|
|Velocity Change 1.9 km/hr (0.53 m/sec)||2.0 km/hr (0.56 m/sec)|
|Extent of contact||Top rail impacts windshield||End of top rail impacts windshield|
|Windshield Damage||Both impacts caused modest cracking but no holes through the glass.|
Damage was limited to moderate windshield cracking, but not to the extent that a driver's ability to see would be severely limited, nor were any holes made through the glass. The results of the testing met the FHWA requirements and, therefore, the Three D Traffic Works Model TD2400 barricade 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.
Please note the following standard provisions which apply to FHWA letters of acceptance:
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety