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NCHRP REPORT 350
DEVICES IN WORK ZONES
CATEGORY 3

Barriers, .crash cushions, TMAs

• Water filled longitudinal channelizing barricades and barriers
• Portable concrete "Jersey" barriers
• Crash cushions and TMAs
• This category also includes ground-mounted signs
• Full NCHRP Report 350 testing applies
• Category 3 devices are subject to the full crash testing requirements of NCHRP Report 350. For Test Level 3 this means a 25 degree hit at 100 kmh with a 4400 pound pickup, and a 20 degree hit with an 1800 pound car.
• Breakaway sign posts are tested with an 1800 pound car at 35 kmh and 100 kmh

Barrier or Barricade?

• A "Barrier" is a longitudinal device that has met the Report 350 criteria for a redirective barrier at TL-2 or above.
• A "Longitudinal Channelizing Barricade" does NOT redirect a vehicle. It is tested at the same speeds and angles, but the vehicle penetrates the barrier without severe forces on the occupant.

Water Filled Longitudinal Channelizing Barricade

Water Filled Barriers

Roadguard (left) with highway kit and Triton barrier (middle, and right) internally reinforced. Both of these proprietary systems have been accepted as BARRIERS. For water filled units to actually perform as a barrier, you must have a steel framework, internal or external.

Temporary Concrete Barrier

The typical pin and loop design that has been in use for years needs to be beefed up in order to meet current crash test criteria. Failures of pin and loop designs have been caused by thin pins pulling out of the loops, loops breaking, or concrete fracturing due to lack of reinforcement. There are nearly a dozen successfully crash tested designs of portable concrete barriers, and they are posted on our web site.

Temporary Barriers

• barrier joints must provide tensile & moment capacity after Oct. 1, 2000
• new units must meet NCHRP 350 after Oct. 1, 2002
• used where vehicle entry to the work zone must be avoided

Temporary Barricades

• Longitudinal Channelizing Barricades
  • Must be tested using same NCHRP Report 350 tests as for a Barrier, but the test vehicle may penetrate the device. The vehicle may not roll over, nor can the device cause excessive forces on the vehicle occupants.
  • Used where vehicle entry behind the line of devices is acceptable.

Work Zone Crash Cushions

Energite III and Quadguard CZ Sand barrel attenuators are initially low-cost but they need nearly total replacement after a hit. More sophisticated attenuators like the Quadguard CZ are quite expensive, but can be restored quickly and cheaply, sometimes without the need to replace any parts at all.

Work Zone Crash Cushions

• Sand Barrel attenuators usually require complete replacement. Should be used where you have the available width, and the frequency of impact will be low
• More sophisticated attenuators are expensive, but easier to repair. They should be used when working widths are narrow and frequency of hits is likely to be high

Truck Mounted Attenuators

TMAs are optional devices, but in order to be acceptable for use they must meet NCHRP Report 350 Test Level 2 criteria at a minimum.

For Additional Information:

Nick Artimovich
FHWA - HSA-10
400 Seventh Street, SW
Washington, DC 20590
mailto:nick.artimovich@fhwa.dot.gov

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