Dr. Ron Faller, Research Assistant Professor 

 Midwest Roadside Safety Facility 

 University of Nebraska – Lincoln 

 527 Nebraska Hall 

 P.O. Box 880529 

 Lincoln, Nebraska 06588-0529 

Dear Dr. Faller: 

Thank you for your letter of October 22, 2004, requesting Federal Highway Administration’s 

(FHWA) acceptance of the Intellistrobe Portable Traffic Control Signal System as a 

crashworthy traffic control device for use in work zones on the National Highway System 

(NHS). Accompanying your letter were reports of crash testing you conducted, 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.” 

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: 

The device’s base is Grade 3003 aluminum and measures 36.25 inches tall by 12 inches deep 

and 16 inches wide. The wall thickness is 0.0875 inch. Hinged, extendable legs are used to 

level the device and to provide stability. The upper portion of the aluminum legs is 1.5 inches 

square and 24 inches long. The lower part is steel and measures 1.0 inches square and 

16.5 inches long. 

400 Seventh St., S.W. 

Washington, D.C. 20590

In Reply Refer To: HSA-10/WZ-195 

December 1, 2004
2

The vertical upright support is 2.0 inch square, Grade 3003 aluminum tubing with 0.125 inch 

wall thickness. It is 12 inches long and is welded to the base unit. The vertical mast is 1.5 inch 

square Grade 3003 aluminum tubing with 0.125 inch wall thickness. It slides inside the 

2.0 inch support and is fastened in place with a 3.0 inch long keeper pin. The signal head 

assembly is a plastic case housing two 12-inch diameter LED lamps. 

The height to the top of the signal base is 37.25 inches, and the height to the top of the signal 

head is approximately 135 inches. The weight of the base plus battery is 93 pounds while the 

mast with signal head weighs 19 pounds. 

Testing 

Bogie testing was conducted on the Intellistrobe devices, with one system being struck in each 

impact. 

The tests are summarized in the table below: 

 Intellistrobe portable traffic control signal system 

Test Number IS-2 IS-3 IS-5 

Version Tested Initial Initial Redesigned 

Orientation End on Head on Head on 

Mounting heights – to top 135 in 135 in 134.5 in 

Weight of Tested Stand 112 pounds 112 pounds 120 pounds 

Mass of Bogie 2467 pounds 

Impact Speed 98.0 km/hr 99.3 km/hr 100.7 km/hr 

Velocity Change 1.2 m/s 1.2 m/s 1.3 m/s 

Extent of contact None in 

windshield area

Portion of leg 

impacted 

windshield 

None in the 

windshield area 

Other notes Acceptable 

performance 

Windshield contact 

led to redesign 

Acceptable 

performance 

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. 

In the present testing, test IS-3 resulted in a portion of a leg break loose and contacting the 

windshield area of the bogie vehicle. Upon redesign of the leg attachment and running of a 

retest, test IS-5, the device performed satisfactorily as the legs remained attached to the base 

cabinet. 
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Findings 

The results of the testing met the FHWA requirements and, therefore, the portable traffic 

control device described above and detailed in the enclosed drawings is 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: 

• 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. 

• 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-195 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 Intellistrobe portable traffic control signal 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 
4

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 H. Kalla/ 

 ~for~ 

John R. Baxter, P.E. 

 Director, Office of Safety Design 

 Office of Safety 

Enclosures 

FHWA:HSA-10:NArtimovich:tb:x61331:11/29/04 

File: h://directory folder/artimovich/WZ195-IntellistrobeFIN 

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

 N.Artimovich, HSA-10)