February 28, 2003

Refer to: HSA-10/WZ – 140

Mr. Greg Hannah
Impact Recovery Systems
246 West Josephine Street
P.O. Box 12637
San Antonio, TX  78212

Dear Mr. Hannah:

This is in response to your letter of December 3, 2002, requesting Federal Highway Administration (FHWA) acceptance of your company's Flexible Traffic Control Products with an Empco Lite 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    Karco Engineering 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.”  


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 the devices follows:

Test Article 1:  12 inch x 48-inch Double sided Vertical Panel with No. 103QR Portable One Base and Light.  The Portable One Base is solid recycled rubber measuring 355 mm (14 inches) wide by 864 mm (34 inches) long and weighing 22 kg (48 pounds).  The vertical panel consists of a 60.3 mm (2 3/8 inch) diameter, 1220 mm tall (48 inch) polyethylene plastic tube.  To the front and back of the tube are attached 305 mm (12 inch) by 1220 mm (48 inch) tall vertical panels.

They are attached to the tube using standard grad 3/8 inch x 2 ¾ inch carriage bolts with tee nuts and plastic washers.

Test Article 2: 24 inch x 36 inch Directional Indicator Barricade with 103QR Portable One base and Light.  The Portable One Base is as described above.  The Directional Indicator Barricade also consists of a polyethylene tube as described above except at a height of 890 mm (35 inches).  To it is attached a single 610 mm (24 inch) tall by 914 mm (36 inch) wide directional panel.


Full-scale automobile testing was conducted on your company' devices.  One stand-alone example of each device 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.  Because the basic structure is the same and both have been previously accepted without warning lights attached, this single test is appropriate for assessing their crashworthiness.  The automobile exceeded the tolerance for the 820C vehicle called for in NCHRP Report 350.  Again, in this case we will accept that because this is a re-test of the device, using lights.

The tests are summarized in the table below.

Test Number


Device Tested

12x48 Vertical Panel

24x36 Directional

Weight of Tested Article

22 kg (48 pounds)

22 kg (48 pounds)

Mounting heights

1220 mm (48 inches)

914 mm (36 inches)

Flags? Lights?

Empco Lite 400T, Type A&C

Empco Lite 600T Type D

Mass of Test Vehicle

962.34 kg

Impact Speed

97.02 km/h

96.98 km/h

Velocity Change



Extent of contact

Grille, hood, windshield, roof

Grille, hood, windshield

Windshield Damage

Minor cracking from impacts with lights, no holes nor deformation

Other notes



Damage was limited to sheet metal damage and minor cracking of the windshield.  The cracking was due to the impact of the plastic lens of the warning light.  The glass did not deform nor was a hole caused by the impact.  As the performance of the conventional Type A and C warning light was comparable to the omni directional Type D light, these two lightweight warning lights may be used interchangeably on these devices.  The results of the testing met the FHWA requirements and, therefore, the devices described in the various requests above and detailed in the enclosed drawings are acceptable for use on the NHS under the range of conditions tested, when proposed by a State.

In a letter dated December 3, 2002, you also asked us to consider the use of warning lights atop your type III barricades. These plastic barricades were the subject of our letter to you, WZ-110, dated March 22, 2002.  Because the top of the barricade struck the test vehicle in the lower part of the windshield causing light to moderate cracking, we expect that the addition of a light would cause additional damage.  Unfortunately, we are not able to estimate how severe the damage would be in the head-on test. Therefore, we must recommend that these barricades be crash tested with lights in place before we can take action.

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

Sincerely yours,

Michael S. Griffith
Acting Director, Office of Safety Design
Office of Safety

2 Enclosures