November 12, 2003
Refer to: HSA-10/WZ-119
Mr. Richard M. Heinz
Endless Visions, Incorporated
Rushville, Illinois 62681
Dear Mr. Heinz:
Thank you for your letter of October 20, 2003, requesting Federal Highway Administration (FHWA) acceptance of your company's J-4 Flagger's Workstation as a crashworthy traffic control device for use in work zones on the National Highway System (NHS). Accompanying your letter was a report of crash testing conducted by the Texas Transportation Institute and a 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."
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.
A brief description of the devices follows:
The J-4 Flagger's Workstation is a Category III portable work zone traffic control device. It is remotely operated by the flagger who is standing in a safer location off of the traveled way. The device consists of a 12-volt battery pack, motor system, push bar handle, 180 degree rotating fiberglass telescopic pole supporting a dual face sign supported by a small steel frame. The portable device is supported by four retractable outriggers when in use and caster wheels when moving from site to site. The outriggers are approximately 1030 mm by 1090 mm in the plan. The device is operated using a control box mounted on a 7.62-m extension cord. The overall height of the device was approximately 3.5 meters, and it weights approximately 93 kg. Details of the workstation are shown in the enclosed drawings for reference.
Full-scale automobile testing was conducted on the workstation. Two stand-alone examples of the device were tested in separate tests, one head-on and another turned at 90 degrees. The crash tests are summarized in the table below:
|Test Article||J4 Head On||J4 90 Degrees|
|Height to Bottom of Sign||2140 mm minimum|
|Height to Top of Sign||3075 mm|
|Flags or lights||Strobe light assembly above STOP/SLOW sign|
|Test Article Mass (each)||93 kg|
|Vehicle Inertial Mass||820 kg||820 kg|
|Impact Speed||99.2 km/hr||99.8 km/hr|
|Velocity Change||3.4 m/s||3.5 m/s|
|Occupant Impact Speed||2.8 m/s||2.9 m/s|
|Vehicle crush||50 mm crush||100 mm crush|
|Occupant Compart. Intrusion||8 mm floor pan deformation||None|
|Windshield Damage||No Contact||No Contact|
Damage was limited to the front right corner of the test vehicle in the head-on impact with a very minor amount of floor pan deformation toward the occupants. The vehicle sustained moderate damage to the right front corner with a maximum exterior crush of 100 mm in the 90 degree impact. No deformation or intrusion into the passenger compartment resulted from the test. 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. The 12 inch diameter reel for storing the communication cable, as described and illustrated in your email messages of October 29, will be acceptable without additional crash testing.
Please note the following standard provisions that apply to FHWA letters of acceptance:
(Original Signed by John R. Baxter)
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety