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U.S. Department of Transportation

Federal Highway Administration

400 Seventh St., S.W.
Washington, D.C. 20590


January 18, 2005

Refer to: HSA-10/WZ-33B

Mr. Frank J. Dvoracek
Three D Traffic Works, Incorporated
430 North Varney Street
Burbank, California 91502

Dear Mr. Dvoracek:

This is in reply to Mr. Kevin King's letter of September 18, 2003, requesting the Federal Highway Administration (FHWA) acceptance of your company's barricades and panel system with attached warning lights as crashworthy traffic control devices for use in work zones on the National Highway System (NHS). Accompanying the letter was a letter report of bogie crash testing conducted by the Midwest Roadside Safety Facility (MwRSF) and video of the tests. Mr. King requested that we find these devices acceptable for use on the NHS under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features." We provided a preliminary response in December of 2003, and you recently asked that this acceptance be formalized.


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:

Three D Traffic Works TD2100 plastic Type I/Type II barricades were found acceptable as Test Level 3 devices in our letter WZ-33 dated May 24, 2000, and WZ-33A dated June 20, 2003, having passed full-scale crash testing. Your present request is for combinations of these barricades supporting 12-foot long 1x8 inch extruded plastic rails, and affixed with warning lights.


Full-scale automobile testing was conducted on your company' 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 tests are summarized in the table below:

Test Number



Barricade Tested

3 Barricades, 2 Boards

2 Barricades, 1 Board



End – on

Weight of Tested Device

39.3 kg (86.7 lbs)

24.1 kg (53.3 lbs)

Height to top of Barricade

960 mm (37.8 in)

972 mm (38.25 in)

Height to top of Board

908 mm (35.75 inches)

908 mm (35.75 in)

Flags? Lights?

3 at 1.2 kg (2.64 lbs)

2 at 1.2 kg (2.64 lbs)

Barricade spacing

3.7 m (12 feet)

3.7 m (12 feet)

Mass of Test Vehicle

929 kg (2049 lbs)

Impact Speed

100.7 km/hr (62.6 mph)

101.4 km/hr (63.0 mph)

Velocity Change

2.9 km/hr (0.8 m/s)

5.5 km/hr (1.5 m/s

Extent of contact

Warning light assembly contacted “windshield”

Board and 1 barricade contacted “windshield)

Windshield Damage

Only minor cracking expected

Only minor cracking expected

This crash-testing program used a hard-nosed bogie vehicle of a mass larger than the standard 820C test vehicle. There are significant constraints involved in using such a non-standard testing device, some of which are:

  1. The potential vehicle velocity change must be considered insignificant.
  2. The crush characteristics of an automobile bumper must not be expected to have a significant affect on the trajectory of the test article.
  3. The profile of the bogie vehicle must be configured to replicate the outline of a production vehicle. The MwRSF bogie was configured to replicate the outline of a Geo Metro, a vehicle commonly used in testing of work zone devices.
  4. No part of the test article may intrude into the windshield area of the vehicle after impact.

The testing met the first 3 criteria but parts of the barricade and panel system contacted the bogie vehicle in the windshield area. In test 3D-1 a warning light detached from its barricade, reflected off the hood, and struck the windshield. In test 3D-2 the lens broke from one light and contacted the center of the windshield. Also in this test the 12 foot long board made glancing contact with the top of the "windshield", and the downstream barricade rotated up and over the hood of the car such that the top of the light impacted in the windshield area. The MwRSF researchers are of the opinion that these contacts would not have caused substantial damage to the windshield should an 820C automobile have been used. Upon reviewing the films of the test we concur in that assessment.


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.

Please note the following standard provisions that apply to FHWA letters of acceptance:

Sincerely yours,

/Original Signed by/

John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety

4 Enclosures

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