Two (2) Truck Mounted Attenuators
The truck mounted attenuator (TMA) shall meet or exceed the specification of the Sa
Stop 180 TMA by Energy Absorption Systems, Inc.
2. The TMA, when properly mounted, shall meet NCHRP (National Cooperative Highway
Research Program) Report 350, Test Level 3 (TL-3) criteria.
3. The TMA equipped truck shall have a maximum skid distance of 8 m (25ft) when
impacted at NCHRP Report 350 TL-3, test 3-51 impact conditions. The forward skid
distance is dependent on the truck’s weight, the truck’s transmission being in second
gear, and the parking brake set with the truck situated on clean, dry pavement.
4. The complete TMA shall be designed to make attachment or detachment from the
truck simple and fast. The major components stay together when detached from the
support vehicle.
5. When the TMA is in an unfolded orientation, the assembly of frames shall be capable
of collapsing when impacted by an errant vehicle. No portion of the TMA shall
protrude forward under the truck damaging its vital elements during an impact.
6. When the TMA folds for transport, no portion of it shall protrude over, into or under
the truck. Further, the folded TMA shall not impede the line-of-site of an Arrowboard
or Message board mounted on the truck, installed per MUTCD (Manual on Uniform
Traffic Control Devices) guidelines at a height of 2135mm (7'-0") to the bottom of
board.
