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                Safety Eligibility Letter WZ-127
  
  **Hardware Type:**
            Work Zone Devices
                          **Code:**
            WZ-127
                          **Date:**
            10/09/2002
                          **Testing Criteria:**
            NCHRP 350
                          **Manufacturer:**
            Yodock Wall Company
                          **Device Description:**
            Yodock 2002 Barrier
                          **View PDF:**
            wz127.pdf (586.73 KB)
    
    
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.
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
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.
 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 U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
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