NCHRP Report 350 Test 3-38 of the Modified Narrow Connecticut Impact Attenuation System (NCIAS) (404231-5)

The objective of this contract is to evaluate the Narrow Connecticut Impact Attenuation System (NCIAS) in accordance with the recommended procedures in National Cooperative Highway Research Program (NCHRP) Report 350. If the NCIAS performs acceptably according to these criteria, the testing program will provide a fully tested impact attenuation system that can be used by Connecticut and other states.This report details the results of the fifth test performed on the NCIAS under this contract, NCHRP Report 350 test designation 3-38. The test involved a 2000-kg pickup truck impacting the critical impact point of the NCIAS at a nominal speed and angle of 100 km/h and 20 degrees. This test is intended to evaluate the potential for pocketing or snagging at the juncture with the object the device is shielding or terminating. Earlier under this study, this test was performed on the NCIAS and did not meet the specifications for test designation 3-38 due to a significant amount of occupant compartment deformation. The deformation was caused as cylinder 8 deformed and allowed the front wheel to contact the backup structure and concrete median barrier (CMB). Cylinder 8 has since been strengthened laterally and the test was repeated. In this repeated test, the modified NCIAS met the specifications for NCHRP Report 350 test designation 3-38.