612.1 Description. This work shall consist of furnishing, installing, operating, maintaining, cleaning, relocating,
replacing and removing impact attenuators as shown on the plans or as directed by the engineer in accordance with the manufacturer's recommendations.
612.2 Material. All material shall be in accordance with Division 1000, Material Details, and specifically as
shown below. Rock salt shall meet the satisfaction of the engineer. Item Section Sand 1005 Retroreflective Sheeting 1042 Temporary Traffic Control Devices 1063
612.3 Safety Requirements. All impact attenuators shall be manufactured specifically for traffic control
purposes and shall be in accordance with the MUTCD and any applicable safety and design codes. Non MASH 2016 impact attenuators manufactured prior to January 1, 2023 may be used until January 1, 2030. All impact attenuators manufactured after January 1, 2023 shall meet MASH 2016 Test Level 3 crash test requirements. The contractor shall submit the manufacturer’s certification that units supplied comply with crash test requirements of NCHRP 350, Test Level 3 or MASH 2016 Test Level 3.
612.4 Construction Requirements.
612.4.1 Truck or Trailer Mounted Attenuator. A truck mounted attenuator (TMA) shall be used as specified in
the contract. Each TMA shall consist of an impact attenuator unit, a support vehicle, and a truck-mounted flashing arrow panel. Trailer mounted attenuators, with support vehicle and mounted flashing arrow panel, may be used in lieu of truck mounted attenuators. Any damaged TMA shall be removed from service and either repaired or replaced to the satisfaction of the engineer.
612.4.2 Impact Attenuator Array (Sand Barrels). Location, and relocation of the impact attenuator arrays
shall be as shown on the plans or as directed by the engineer.
612.4.2 1 Sand shall be measured and placed in accordance with the manufacturer's recommendations and
weights shown for each module. Sand shall have a maximum moisture content of five percent at the time of installation. Rock salt shall be five percent of the required weight in each module, and shall be uniformly dispersed in the sand.
612.4.2 2 A decal designed as a Type I object marker with fluorescent orange retroreflective sheeting or a Type 3
object marker with yellow sheeting shall be applied to the lead module facing traffic for arrays located 12 feet or less from the edge of the traveled way.
612.4.2 3 Damaged or deficient modules shall be replaced by the contractor in accordance with Sec 616.4.
612.4.2 4 When no longer needed, modules and sand shall be removed and shall remain the property of the
contractor.
612.4.3 Work Zone Crash Cushion. Location and relocation of the crash cushion shall be as shown on the
plans or as directed by the engineer.
612.4.3 1 Water-filled crash cushions shall be filled and contain a mixture to prevent freezing in accordance with
the manufacturer's recommendations.
612.4.3 2 Damaged or deficient modules shall be replaced by the contractor in accordance with Sec 616.4.
612.4.3 3 When no longer needed, work zone crash cushions shall be removed and shall remain the property of
the contractor.
612.5 Basis of Payment.
612.5.1 No payment will be made for truck mounted attenuators (TMAs) used in mobile operations or for any
TMAs designated as optional. TMAs required for stationary work activities will be paid as specified in the contract.
612.5.2 Impact attenuator arrays (sand barrels), will be paid for at the contract unit price for each impact
attenuator array per the manufacturer’s recommendations for the posted speed limit. Relocation of impact attenuator arrays will be paid for at the contract unit price included in the contract. Work zone crash cushions will be paid for at the contract unit price. Relocation of work zone crash cushions will be paid for at the contract unit price.
612.5.2 1 Furnishing and installing replacement sand barrels will be paid for at the contract unit price per each
sand barrel. Final payment for this item will be based on the actual number of modules replaced. Replacement of damaged work zone crash cushions is incidental and shall be replaced at no cost to the Commission.
Impact Attenuators in other states
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