Phase I development of a non-proprietary, four-cable, high tension median barrier.

Final report; 2003-2011.PDFTech ReportTRP-03-213-11SPR-3(017) supplement #36SPR- 3(017) supplement #35Median barriersMediansTensionRope, wire and cableCablesGuardrailsImpact testsAcceptance testsHighway safetyDitchesNebraskaMidwest Roadside Safety FacilityWiebelhaus, Mitch J.Johnson, Erin A.Sicking, Dean L.Faller, Ronald K.Lechtenberg, Karla A.Rohde, John R.Bielenberg, Robert W.Reid, John D.Rosenbaugh, Scott K.Midwest Roadside Safety FacilityNebraska. Dept. of RoadsUnited States. Federal Highway AdministrationNTL-SAFETY AND SECURITY-Highway SafetyNTL-OPERATIONS AND TRAFFIC CONTROLS-OPERATIONS AND TRAFFIC CONTROLSNTL-HIGHWAY/ROAD TRANSPORTATION-Bridges and StructuresUS Transportation CollectionDuring the last decade, the use of cable median barriers has risen dramatically. Cable barriers are often utilized in depressed medianswith widths ranging from 30 to 50 ft (9.1 to 15.2 m) and with fill slopes as steep as 4H:1V. Although cable barriers have been shown to containand redirect many heavy trucks, a careful review of accident records has indicated that passenger vehicles do occasionally penetrate through thestandard 3-cable median barrier and enter opposing traffic lanes. As a result, the Midwest States Pooled Fund Program sponsored a research anddevelopment project to improve the safety performance of existing, non-proprietary, cable median barriers. These safety improvements includedincreased cable spacing, increased cable height, the use of four cables, increased cable tension, and optimized cable attachment to posts.Three Test Level 3 crash tests were performed on a four-cable, high-tension median barrier placed in a 46-ft (14.0-m) wide, 4H:1VV-ditch. All tests were conducted according to the safety performance guidelines provided in the Manual for Assessing Safety Hardware(MASH). The first test utilized a 2270P pickup truck impacting the barrier placed on a downslope and 12 ft (3.7 m) laterally away from the frontslope break point. The vehicle was contained and redirected by the barrier and deemed acceptable according to the MASH guidelines. The secondtest utilized a 1100C small car impacting the barrier placed 27 ft (8.2 m) laterally away from the front slope breakpoint or 4 ft (1.2 m) up the backslope of the V-ditch. During the second test, the small car impacted the ditch bottom with a soft-soil condition and began to plow into the soil,thus causing moderate decelerations and velocity change before contacting the barrier and a marginal impact performance. The third test utilizeda 1100C small car impacting the barrier in the same position as used in the second test. During the third test, the small car impacted the ditchbottom with a hard-soil condition and was contained by the barrier. However, excessive roof crush resulted when one of the cables slide up thevehicle and later snagged on the cable-to-post attachment hardware, thus resulting in a failed test. Design modifications are anticipated in a PhaseII R&D effort