Mr. Keith Callaway 

 MDI Traffic Control Products 

 38271 W. Twelve Mile Road 

 Farmington Hills, Michigan 48331-3041 

Dear Mr. Callaway: 

Thank you for your letter of April 13, 2005, requesting the Federal Highway Administration’s 

(FHWA) acceptance of an aluminum rectangular sign with your company’s 4860K Breakaway 

Stand as a crashworthy traffic control device for use in work zones on the National Highway 

System (NHS). Accompanying your letter drawings of the stand with the various signs in 

place. You 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.” 

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 device follows: 

Model 4860K, with breakaway feature, tested with Aluminum panel and light: 

(This stand was originally accepted in the FHWA acceptance letter WZ-69 dated May 9, 2001, 

and was the subject of Test MDI 6) 

This stand is manufactured with two vertically mounted steel coil springs to support 1219 

x 1219 x 2 mm (48 x 48 x 0.080 inch) aluminum signs. The four legs of the stand are 32 x 32 

x 2.5 mm (1.25 x 1.25 x 0.10 inch) square 6061-T6 extruded aluminum tubing. The coil 

400 Seventh St., S.W. 

Washington, D.C. 20590

In Reply Refer To: HSA-10/WZ-211 

June 17, 2005 
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springs attach the 5 mm (0.19 inch) thick autophoretic coated steel base to the telescoping 

upright. The two-piece, upright, consisting of a 38 mm (1.50 inch)(bottom) and a 32 mm 

(1.25 inch)(top) square aluminum tube, supports the sign. The bottom upright has a scored 

“breakaway section” at 483 mm (19 inches) above grade when the stand is fully assembled. 

Rigid sign mounting brackets support the aluminum sign at top and bottom and a steel flag 

lock bracket is attached to the top upright supporting three hardwood dowel flags. A barricade 

light assembly, consisting of two a 6-volt battery batteries and a 178 mm (7 inch) 

polycarbonate lens, is mounted to the top upright above the flag bracket. 

The overall height of the stand, with flags and light is 4115 mm (162 inches) and 3251 mm 

(128 inches) without the light and flags. The bottom of the sign is mounted 1524 mm 

(60 inches) above grade. The total weight of the sign stand is 31.6 kg (69.7 pounds) which 

includes the stand of 21.7 kg (47.7 pounds), the sign and flags of 8.4 kg (18.5 pounds) and the 

light of 1.6 kg (3.5 pounds) as tested in MDI 6. 

Testing 

Full-scale automobile testing was conducted on your company’ devices. As reported in WZ-69 

there was no damage to the windshield as the mast separated at the base and the sign and mast 

components rotated up and impacted the roof. 

Your request is that the 4860K Breakaway stand be found acceptable with the following 

48 x 60 (vertical) sign substrates listed with their approximate weights: 

1) 5/8” plywood 44 pounds 

2) 0.080 aluminum 24 pounds 

3) 0.100 aluminum 30 pounds 

4) 0.125 aluminum 37 pounds 

5) 5/8” Endurance 13.3 pounds 

6) Aluminum Laminate 13.3 pounds 

The tested sign was a 20-pound 48 x 48 aluminum sign. Sign substrates 1) through 4) are 

heavier than the tested system and should, after impact, allow the sign and mast to rotate about 

its center of gravity, moving up and away from the windshield. Substrates 5) and 6) may also 

go over the roof, but are light enough that there should be no significant damage to the 

windshield should the mast or sign impact it. 

Findings 

We concur in your assertion that the 4860K Breakaway sign stand with a 48 x 60 sign will 

perform in a similar manner to the tested system, therefore, the devices described above and 

detailed in the enclosed drawings are acceptable for use on the NHS under the range of 

conditions the 4860K Breakaway Stand was tested, when proposed by a State. 

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

• Our acceptance is limited to the crashworthiness characteristics of the devices and does 

not cover their structural features, nor conformity with the Manual on Uniform Traffic 

Control Devices. 
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• Any changes that may adversely influence the crashworthiness of the device will require 

a new acceptance letter. 

• Should the FHWA discover that the qualification testing was flawed, that in-service 

performance reveals unacceptable safety problems, or that the device being marketed is 

significantly different from the version that was crash tested, it reserves the right to 

modify or revoke its acceptance. 

• You will be expected to supply potential users with sufficient information on design and 

installation requirements to ensure proper performance. 

• You will be expected to certify to potential users that the hardware furnished has 

essentially the same chemistry, mechanical properties, and geometry as that submitted for 

acceptance, and that they will meet the crashworthiness requirements of the FHWA and 

the NCHRP Report 350. 

• To prevent misunderstanding by others, this letter of acceptance, designated as number 

WZ-211 shall not be reproduced except in full. This letter, and the test documentation 

upon which this letter is based, is public information. All such letters and documentation 

may be reviewed at our office upon request. 

• The MDI 4860K Breakaway Sign Stand is a patented device and is considered 

"proprietary." The use of proprietary work zone traffic control devices in Federal-aid 

projects is generally of a temporary nature. They are selected by the contractor for use as 

needed and removed upon completion of the project. Under such conditions they can be 

presumed to meet requirement "a" given below for the use of proprietary products on 

Federal-aid projects. On the other hand, if proprietary devices are specified by a highway 

agency for use on Federal-aid projects they: (a) must be supplied through competitive 

bidding with equally suitable unpatented items; (b) the highway agency must certify that 

they are essential for synchronization with existing highway facilities or that no equally 

suitable alternative exists or; (c) they must be used for research or for a distinctive type of 

construction on relatively short sections of road for experimental purposes. These 

provisions do not apply to exempt non-NHS projects. Our regulations concerning 

proprietary products are contained in Title 23, Code of Federal Regulations, Section 

635.411, a copy of which is enclosed. 

• This acceptance letter shall not be construed as authorization or consent by the FHWA to 

use, manufacture, or sell any patented device for which the applicant is not the patent 

holder. The acceptance letter is limited to the crashworthiness characteristics of the 

candidate device, and the FHWA is neither prepared nor required to become involved in 

issues concerning patent law. Patent issues, if any, are to be resolved by the applicant. 

Sincerely yours, 

 

 /original signed by/ 

John R. Baxter, P.E. 

 Director, Office of Safety Design 

 Office of Safety 

Enclosures 
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FHWA:HSA-10:NArtimovich:tb:x61331:6/13/05 

File: h://directory folder/artimovich/WZ211-midiFIN 

cc: HSA-10 (Reader, HSA-1; Chron File, HSA-10; 

 N.Artimovich, HSA-10)