Refer to: HSA-10/WZ-127

Mr. Leo J. Yodock 

Yodock Wall Company 

623 N.E. Fifth Terrace 

Fort Lauderdale, Florida 33304 

Dear Mr. Yodock: 

This is in response to Dr. Dean Alberson’s letter of April 29, 2002, and your e-mail message of 

August 15, 2002, requesting Federal Highway Administration (FHWA) acceptance of a variation 

to your company=s Type III barricade device as a crashworthy traffic control device for use in 

work zones on the National Highway System (NHS). Dr. Alberson indicated that you wish to 

omit the striped barricade rails but retain the sign panel, resulting in a temporary sign support. 

He requested that we find this device 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 “Yodock 2001 

Barrier with T3 apparatus” with no water ballast was successfully tested as a Type III barricade 

and found acceptable in our March 23, 2000, letter to you designated as WZ-34. A modified 

version with the barricade rails mounted higher, and supporting a 48 x 48 inch diamond sign, 

was crash tested head-on with the unit filled with water. This version was found acceptable for 

use as a road-closure device, subject to limitations of the volume of water used as ballast, in our 

February 7, 2002, letter to you designated as WZ-107. 

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 AINFORMATION: Crash Tested Work Zone Traffic 

Control Devices.” This later memorandum lists devices that are acceptable under Categories I, 

II, and III. 
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The subject sign stand would support the sign at 60 inches from the ground to the base of the 

sign. The stand consists of a Yodock Model 2001 segment, two two-inch schedule 80 PVC 

posts, a striped horizontal barricade panel supporting two lightweight warning lights, and the 

plywood sign panel. The striped barricade panel is hollow plastic lumber weighing 

approximately 3.5 pounds per six-foot length.

Testing – WZ-34 

Full-scale automobile testing was conducted on the “Yodock 2001 Barrier with T3 

apparatus”. Two stand-alone examples of the 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. Each barricade consisted of a polyethylene plastic segment with three barricade 

rails and warning lights. Each Model 2001 segment had a base 610 mm (24 inches) wide, and 

was 1170 mm (46 inches) tall. Each segment is 1820 mm long (71.5 inches). Inserted at the top 

of each segment were two poles for the top “T3” apparatus consisting of the barricade rails and 

the warning lights. Two barricade rails are mounted on the face of the barrier segment while the 

third is affixed to the poles. The mass of the 2001 segment itself was 61 kg (135 pounds), 

increasing to 81 kg (180 pounds) with the addition of the T3 apparatus. Although the Yodock 

2001 segments are made to hold water, no water was used in the test. 

Upon impact the T3 units separated from the “2001” plastic base segments and traveled over the 

roof of the test vehicle. The first plastic base segment traveled over the vehicle and the second 

(90 degree hit) pushed the hood upwards into the windshield. There was moderate cracking of 

the windshield but was judged not severe enough to prevent the driver from navigating the 

vehicle to a safe stop. There was no occupant compartment intrusion or significant deformation 

observed, nor did any test article debris show potential for penetrating the occupant 

compartment. 

Testing – WZ-107 

One head-on, full-scale automobile test was conducted with the Yodock Barrier Model 2001 

Energy Dispersement Cell Barricade (EDCB) units. The EDCB units are rotomolded, 

low-density polyethylene (LDPE), water-filled containers. Overall dimensions on these 

New Jersey barrier-shaped units are 1830 mm(72 inches) long, 1170 mm (46 inches) tall, 

610 mm (24 inches) width at the base, and 280 mm (11 inches) wide at the top. There are two 

forklift holes at 530 mm (21 inches) above ground level that nominally measure 150 mm x 280 

mm (6 x 11 inches). The bottom vertical face of the device is 230 mm (9 inches) in height. For 

this test, water ballast was placed in the units to the maximum capacity. The approximate full 

mass of each unit is 708 kg (1560 pounds.) A total of three units were placed adjacent to each 

other and coupled with Polyethylene couplers. The total length of the installation was 5.5 m 

(18 ft.) 

The Type III barricade atop each water filled unit was fabricated with two 50 mm (2 inch) 

schedule 80 PVC pipes, 2.59 m long (102 inch) supports. The center of the support pipes are 

placed 330 mm (13 in) from each end of the units. Hollow plastic lumber measuring 20 mm (3/4 

inch) thick, 195 mm (7.7 inches) tall, by 1840 mm (72.4 inches) long was attached to the PVC 
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pipe with 6 mm (1/4 inch) “U” bolts. The top of the middle horizontal panel was 1940 mm 

(76.4 inches) above the ground. The top of the upper horizontal panel was mounted 2440 mm 

(96 inches) above grade. In addition, a 1220 mm x 1220 mm x 12 mm (4 foot x 4 foot x 

7/6 inch) plywood sign panel was bolted to the middle Type III barricade. The top of the sign 

panel was 3250 mm (128 inches) above grade. Four battery powered warning lights were 

attached to the top of the pipe supports. 

In the EDCB test, the vehicle broke through the middle barricade, pulling those to the right and 

to the left along with it for a short distance. The impact forced the hood back into the 

windshield, causing a hole in the glass. Even though the test resulted in a hole in the windshield, 

parts of the device itself did not show potential for penetrating the occupant compartment. 

Because of the mass of the water in the filled cells, Occupant Impact Velocity exceeded that for a 

breakaway work zone traffic control device. However, it was within the desirable limit for a 

crash cushion impact and is considered survivable 

Findings 

The damage sustained by the test vehicles was moderate, with no occupant compartment 

intrusion caused by the barricade rails, uprights, or the sign. The velocity change in the unit 

filled with water was unacceptable, and therefore was limited to 363 kg (800 pounds) of water. 

The results of the testing met the FHWA requirements. 

In his letter Dr. Alberson explains that the modification you requested would perform in an 

acceptable manner because the sign would break free and follow a trajectory over the vehicle. 

Based on the crash testing of the Type III Barricade variations, we concur that the Yodock Sign 

Support described above and shown in the enclosed drawings for reference is acceptable for use 

on the NHS under the range of conditions tested, when proposed by a State. 

We also concur that a similar sign support system, using the smaller Yodock 2001m module, 

would also be acceptable under the same conditions. The 2001m module with T3m apparatus 

was successfully crash tested and found acceptable in our letter WZ-22 dated October 19, 1999. 

This letter also supercedes WZ-34 as the acceptance letter for the “Yodock 2001 Barrier with 

T3 apparatus. This device, also described above and illustrated 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. 
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! 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 FHWA and 

NCHRP Report 350. 

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

WZ-127 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 Yodock walls are patented components and are 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 for use on Federal-aid projects, 

except exempt, non-NHS 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. Our 

regulations concerning proprietary products are contained in Title 23, Code of Federal 

Regulations, Section 635.411, a copy of which is enclosed.

Sincerely yours, 

Carol H. Jacoby, P.E. 

 Director, Office of Safety Design 

Enclosure