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 U.S. Department of Transportation Federal Highway Administration |
Home > Roadway Departure Safety > Policy/Guidance > Roadside Hardware Policy and Guidance > Barrier Terminals/Crash Cushions |
February 9, 2005
In Reply Refer To: HSA-10/CC-85A
Mr. Randy L. Warner
Director, Product R&D
SCI Products Incorporated
635 Lucknow Road
Harrisburg, Pennsylvania 17110-1635
Dear Mr. Warner:
Your December 22, 2004, letter requested formal Federal Highway Administration (FHWA) review and acceptance of a Test Level 2 (TL-2) version of your TL-3 crash cushion called the Smart Cushion Innovations – 100GM (SCI-100GM) that was previously accepted for use on the National Highway System (NHS). To support this request, you sent copies of test reports prepared by KARCO Engineering detailing the results of the full-scale crash tests you conducted on the new TL-2 attenuator called the SCI-70GM crash cushion. You later submitted information on the crash cushion design and identified changes from the TL-3 model. This information had not been included in the original KARCO test report.
The SCI-70GM is a redirective, non-gating crash cushion, 4118 mm long and 850 mm high. Its main components, as shown in Enclosure 1, are identical to the SCI-100GM design and include base and side frame assemblies fabricated of mild steel tubing, a front sled assembly, and a series of 10-gauge galvanized Grade 60 steel side panels mounted to collapsing steel frames, and a shock arresting cylinder. A 1.125-inch diameter steel cable is attached to the front sled assembly and is then routed around a front sheave to dual sheave assemblies located at the back of the attenuator (one at either end of the shock arresting cylinder). The SCI-70GM is 3 bays shorter than the TL-3 design and the cylinder stroke was reduced accordingly. The base unit is anchored to the mounting substrate with 34 bolts. Testing was performed on a unit mounted on a concrete pad with galvanized Grade B7 all-thread rods 0.75-inches in diameter and seven inches long. These rods were inserted into .875-inch diameter holes and set with epoxy.
You conducted two certification tests: National Cooperative Highway Research Program (NCHRP) Report 350 tests 3-31 and 3-32, the results of which are summarized in Enclosure 2. Staff members agreed beforehand that test 3-30 could be waived because test
3-32 is more demanding for the small car. It was also agreed that all redirective tests could be waived since the crash cushion design remained essentially unchanged along its sides and there was no concern that crash performance would be adversely affected in the lower speed TL-2 side impact tests.
Your SCI-70GM meets the evaluation criteria for an NCHRP Report 350 redirective,
non-gating crash cushion at TL-2 and may be used on the NHS when such use is acceptable to the contracting authority. Requirements for transition designs remain as stated in acceptance letter CC-85 for your TL-3 unit.
Please note also that the following provisions apply to the FHWA letters of acceptance:
