Federal Highway Administration
1200 New Jersey Ave. S.E.
Washington, D.C. 20590
June 27, 2008
In Reply Refer To:
Mr. David E. Wasserstrom
Trident Security Devices, Inc.
P.O. Box 26716
Elkins Park, PA 19027
Dear Mr. Wasserstrom :
This letter is in response to mail correspondence of January 4, 2007, requesting the Federal Highway Administration’s (FHWA) acceptance of your company's ROADGUARD/2 Longitudinal Channelizer for use on the National Highway System (NHS) under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features." Accompanying the letter was a report on testing of your company's ROADGUARD/2 prepared by Transportation Research Center Inc., including test videos and drawings.
Longitudinal channelizing barricades (LCBs) are classified as work zone traffic control devices and should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features." The FHWA Memorandum “ACTION: Identifying Acceptable Highway Safety Features” of July 25, 1997, provides further guidance on crash testing of work zone traffic control devices.
The ROADGUARD/2 Longitudinal Channelizing Barricade system consists of water filled UV-resistant polyethylene barricades, each consisting of two equal chambers that are manufactured from High Density Polyethylene (HDPE) plastic. Each barricade weighs approximately 19.3 kg (42.5 lbs) empty and each unit has the capacity to be filled with 340 liters (90 gallons) of water in each of the two chambers. Drawings of your company's ROADGUARD/2 are enclosed.
Test article installation
The test article consisted of 10 interlocking barricades, positioned in a straight line. Each chamber of each individual barricade was filled with approximately 20.5 liters (5.4 gallons) of water. The overall length of the 10 interlocking barricades was approximately 60 feet. Details of the test article installation are enclosed.
The NCHRP Report 350 requires that in order for work zone traffic control devices to meet test level 3 (TL-3) criteria, they must successfully pass tests 3-70 and 3-71. The low-speed test 3-70, where a 820C vehicle impacts the device at 35 km/h, evaluates the breakaway, fracture, or yielding mechanism of the device along with the occupant risk and may be omitted if it can be shown that it is less critical than the high speed test.
Since your company’s ROADGUARD/2 LCB is intended to be used for highway applications ballasted with no more than 20.5 liters (5.4 gallons) of water in each of two chambers of each barricade, it has a relatively small mass. Therefore, test 3-71 was conducted and test 3-70 was omitted on your company’s LCB because the high speed test is deemed more critical.
Test 3-71 involved the 820C vehicle impacting the center of barricade number 5 at 100.5 km/h and a 20 degree angle. The vehicle continued in a forward direction after impact, penetrated through the LCB, and disconnected the units from each other. From the test video, it was observed that the vehicle’s right front wheel started to ride up barricade number 6 and both right front and back wheels became airborne. However, the vehicle remained upright throughout the test event with maximum roll, pitch and yaw angles of 23.2, 6.2 and 22.1 degrees respectively.
Five of the ten individual barricade sections that made up the test article were displaced beyond the immediate impact zone and four of them incurred damage to their overall outer shell sidewalls. No measurable crush was evident to the occupant compartment of the vehicle. The occupant impact velocity was 6.7 m/s in the longitudinal direction, and 0.4 m/s in the lateral direction. The highest occupant ridedown acceleration was 5.6 g’s in the longitudinal direction and 3.0 g’s in the lateral direction. While the occupant impact velocity in the longitudinal direction exceeds the maximum NCHRP 350 limit of 5 m/s for test 3-71, it is within the maximum NCHRP 350 limit of 12 m/s for longitudinal barriers and gating end treatments. Given the nature of your device as a LCB, it is agreed that 12 m/s may be used as an occupant impact velocity criterion for this test.
In summary, the ROADGUARD/2 Longitudinal Channelizing Barricade, as described above, meets the appropriate evaluation criteria for the NCHRP 350 TL-3 work zone traffic control devices and may be used at all appropriate locations on the NHS when selected by the contracting authority. This device is accepted by the FHWA for use under the range of conditions tested and may be used with up to 20.5 liters (5.4 gallons) of water in each chamber to provide enough ballast to keep the barricades from being displaced by wind. As the quantity of water used for ballast may substantially affect the performance of the longitudinal channelizing barricades, a permanent indication should be applied to each unit notifying users of this limitation.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
George E. Rice, Jr.
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