Refer to: HSA-10/WZ-106

Mr. Leo J. Yodock, III
Yodock Wall Co., Inc.
Ft. Lauderdale, FL  33315

Dear Mr. Yodock:

Thank you for your letter of September 4, 2001, requesting Federal Highway Administration (FHWA) acceptance of your company's Energy Dispersement Cell Channelizer (EDCC) as a crashworthy traffic control device for use in work zones on the National Highway System (NHS).  Accompanying your letter was a report of crash testing conducted by the Texas Transportation Institute and videos of the tests. You requested that we find this device acceptable as a Test Level 2 (TL-2) device 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.”

On December 13, 2001, you met with members of the Office of Safety Design staff to discuss the crash-testing program, the results, and the proposed uses associated with these devices.  On January 9,2002, you submitted additional information as discussed at our meeting.


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 follows:

Energy Dispersement Cell Channelizer  - TL-2               

The Yodock Barrier Model 2001 EDCC units are rotomolded, low-density polyethylene, containers that can be partially filled with water as ballast.  Overall dimensions on the units are 1830 mm long, 1170 mm tall, 610 mm width at the base, and 280 mm wide at the top.  There are two forklift holes at 530 mm above ground level that nominally measure 150 mm x 280 mm.  The bottom vertical face of the device is 230 mm in height.  Water ballast was placed in the units to the top of the vertical face located approximately 495 mm from the base of the device.  The approximate measured volume of water in each unit was 170 L (45 U.S. Gallons.)  A total of 40 units were placed adjacent to each other and coupled with Polyethylene couplers.  Total length of the installation was 73.2 m (240 feet.)  An internal flashing beacon and solar battery, weighing 4.0 kg, was installed on segments 13 and 14.  Details of the EDCC units and couplers are shown in the enclosed drawings for reference.

This device was evaluated as a longitudinal channelizing barricade.  This is a subcategory of barricades now being considered for inclusion in the Manual on Uniform Traffic Control Devices (MUTCD).  They can be used singly as Type I, II or III barricades, or connected so they are highly visible and have good target value.  The interlocking units of a longitudinal channelizing barricade can be used to delineate or channelize traffic flow including pedestrian traffic.  The interlocking barricade does not have gaps through which pedestrians, bicyclists, or motor vehicles can filter.  However, it is not designed to prevent penetration by vehicles under minimum crash test performance conditions.  After discussions with my staff, it was determined that NCHRP Report 350 test 2-10 (820 kg passenger car impacting at 70 kmh at an angle of 20 degrees) would be appropriate; however, when evaluating its performance as a longitudinal channelizer barricade during this test, occupant risk and vehicle stability should be the determining criteria, and not structural adequacy.  In other words, when the EDCC are used for channelizing, it would be acceptable for the vehicle to penetrate the longitudinal channelizer barricade in a safe manner.


Full-scale automobile testing was conducted on your company's device.  The test results are summarized in the following table.

Test Number


NCHRP Report 350 Test #


Test Article

Longitudinal Channelizer

Height to Bottom of Sign


Height to Top of Sign


Flags or lights


Test Article Mass (each)

60 kg + 200 kg water

Vehicle Inertial Mass

820 kg

Impact Speed

68.3 km/hr

Occupant Risk Values

  Occupant Impact Velocity

7.0 m/s

  Ridedown x-direction

-4.9 g's

  Ridedown y-direction

-4.3 g's

  Max 0.050-s accel x-dir

-5.9 g's

  Max 0.050-s accel y-dir

-3.6 g's

  Max 0.050-s accel z-dir

-2.5 g's

Vehicle crush

100 mm

Occupant Compartment Intrusion

92 mm (crush)

Windshield Damage


In the test of the EDCC the vehicle penetrated the channelizer and yawed sharply.  The side of the car then struck the exposed blunt end, causing minor deformation of the passenger compartment at the door.  The resulting deformation has a low potential to cause serious injury to occupants of the impacting vehicle.  The vehicle traveled 6.1 m behind the channelizer before coming to rest.


The EDCC does not meet the redirective requirements for a barrier.  However, as a longitudinal channelizer it can provide an unbroken line of units that warn motorists from crossing into the protected area.

Because this device has been tested and met the unique requirements that have been set for them, the device described above and shown in the enclosed drawings for reference are acceptable for use on the NHS under the range of conditions tested and the additional conditions discussed above, when proposed by a State.  In addition, the Model 2001m EDCC, which is 812 mm tall, will also be acceptable subject to the same conditions and restrictions as the crash-tested Model 2001 EDCC.

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

Sincerely yours,

Michael L. Halladay

Acting Program Manager, Safety