November 26, 2002

Refer to: HSA-10/WZ-125

Mr. Grant Dicke
Dicke Tool Company
1201 Warren Avenue
P.O. Box 518
Downers Grove, Illinois  60515

Dear Mr. Dicke:                                                           

Thank you for your letter of March 29, 2002, and facsimile message of November 21, 2002, requesting Federal Highway Administration (FHWA) acceptance of your company's portable sign stands as crashworthy traffic control devices for use in work zones on the National Highway System (NHS).  Accompanying your letter was a report of crash testing conducted by the Midwest Roadside Safety Facility.  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.”  Most of the sign support systems that were tested in this phase were reviewed previously and are the subject of our November 21, 2001, letter to you, designated WZ-99.  This present letter of acceptance, WZ-125, will only deal with the one remaining sign stand that was tested with successful results.


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 AINFORMATION: 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:

Systems 58 and 59, Test No. D-30 DF-4000 Stand - A heavy duty, double torsion spring mounted portable sign support with a 1219 x 1219 mm vinyl sign mounted at a height of 305 mm from the ground and with three wood-staffed flags at a height of 2299 mm. This stand supported a RUNR48 reflective vinyl roll up sign.  Tested at both 90 degrees and head-on.


Full-scale automobile testing was conducted on your company's devices.  Two stand-alone examples of the device were tested in tandem, one oriented at 90-degrees (i.e., turned away from oncoming traffic) and the next placed six meters downstream head-on, as called for 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


Test Article

DF-4000 sign stand with RUNR48 vinyl roll up sign

Height to Bottom of Sign

305 mm

Height to Top of Sign

2013 mm

Flags or lights

3 flags on wood dowels, 2927 mm to top of flags

Test Article Mass (each)

19.05 kg

Vehicle Inertial Mass

812 kg

Impact Speed, Head-on

103.6 km/hr

Impact Speed, 90 Deg.

100.7 km/hr

Velocity Change, Head-on

0.81 m/s

Velocity Change, 90 deg.

Not recorded

Vehicle crush

Dents on hood and rear of roof

Occupant Compart. Intrusion


Windshield Damage

Minor “spider web” cracking plus single crack from top to bottom near center of windshield.


Damage was limited to dents, and minor windshield cracking.  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,

Carol H. Jacoby, P.E.
Director, Office of Safety Design