Refer to: HSA-10/WZ-100 Amendment #1

Mr. Bill Korman
Korman Signs, Incorporated
3029 Lincoln Avenue
Richmond, Virginia 23228

Dear Mr. Korman:

This is in response to your letter of November 14, 2002, requesting Federal Highway Administration (FHWA) acceptance of a number 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 were reports of crash testing conducted by General Testing Services and 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." As many of the stands are already covered under FHWA Acceptance Letter WZ-100, originally issued on June 20, 2002, you asked that we consider this a request to amend WZ-100 with the updated information.

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 your requests, including designation of the sign stands and the sizes and substrates you wish to use follows:

Request Number 1:

Stands: SS548 UCA, SS548UC

Signs: 60x60 or smaller Diamond or Square

48x60 or smaller Rectangle

Substrates: Alpolic 350 with a one or two piece fiberglass rib adapter fastened to the back of the sign a minimum of of the sign height to allow mounting to a stand in the same fashion that a roll up sign is mounted.

Mounting Ht: 21 inches

Other: With or without flags or ballast

Request Number 2:

Stands: SS548UCRA, SS548UCR, SS560UCRA, SS560UCR

Signs: 60x60 or smaller Diamond or Square

48x60 or smaller Rectangle

Substrates: Alpolic 350 with a one or two piece fiberglass rib adapter fastened to the back of the sign a minimum of of the sign height to allow mounting to a stand in the same fashion that a roll up sign is mounted.

Other: With or without flags or ballast

Mounting Ht: 13 inches

Request Number 3:

Stands: SS548SSUC, SS548SSUCA

Signs: 60x60 or smaller Diamond or Square

48x60 or smaller Rectangle

Substrate: Alpolic 350 with a one or two piece fiberglass rib adapter fastened to the back of the sign a minimum of of the sign height to allow mounting to a stand in the same fashion that a roll up sign is mounted.

Other: With or without flags or ballast

Mounting Ht: 21 inches

Enclosure #1 is a summary of the acceptances that this request embraces, with an indication of the mounting height of each sign that was tested and is to be considered for acceptance.

Testing

Full-scale automobile testing was conducted on your company's devices. Two stand-aloneexamples 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. Enclosure #2 is a summary of the crash tests conducted to support the requests. Enclosure #3 is another summary which relates the individual stands to the tests conducted as part of this submission, as well as to earlier FHWA letters of acceptance which support the individual request. Enclosure #4 is a summary of the product description and a glossary of terms used to describe the variations in your company's stands. Enclosure #5 contains a drawing of each stand, for reference.

The test run to verify performance of the practice of affixing a partial mast to the back of the Alpolic 350 substrate is summarized in the table below.

  Test Session # 20
Test Number 100A (Head-on) 100B (90 degrees)
Sign Stand Tested SS548UCA S484DAPUC
Weight of Tested Stand 24 pounds 24 pounds
Mounting heights 21 inches 21 inches
Flags? Lights? None None
Mass of Test Vehicle Approx 1800 pounds
Impact Speed Approx 58 mph Approx 58 mph
Velocity Change NR NR
Extent of contact Sign struck windshield Sign struck windshield
Windshield Damage Moderate cracking Moderate cracking
Other notes Concentrated cracking at point of impact Concentrated cracking at point of impact, deflection no greater than inch

Findings

Damage was limited to moderate cracking of the windshield plus minor damage to the bumper, hood, and roof of the test vehicle. There were no instances of passenger compartment penetration or intrusion.

Requests 1 and 2 are for stands included in acceptance letters WZ-21, WZ-29, and WZ-100. This amendment adds the Alpolic 350 sign panel with a half-height fiberglass vertical rib attached to the back of the sign. This allows its use with these stands in the same manner as a roll-up sign. Request 3 is for a single-spring version of previously accepted stands.

The results of the testing met the FHWA requirements and, therefore, the devices described in the various requests above and detailed in the enclosed tables and 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,

Harry W. Taylor,
Acting Director, Office of Safety Design

Enclosure