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ABSTRACT

The Manual for Assessing Safety Hardware (MASH) specifies six test levels of increasing demand on roadside and median barrier systems. The most challenging impact conditions correspond to MASH Test Level 6 (TL-6), which consists of an 80,000-lb tractor-tank trailer vehicle impacting the barrier system at 50 mph and 15 degrees. Typically, tall barriers are used to contain and redirect tractor-tank trailer vehicles due to the elevated height of the liquid ballast compared to other commercial truck vehicles. Previous testing at the Texas A&M Transportation Institute (TTI-TAMU) showed satisfactory redirection of 80,000-lb tractor-tank trailer vehicles produced in the 1970s impacting at 50 mph and 15 degrees with 90-in. tall barrier systems. The Midwest Roadside Safety Facility (MwRSF) embarked to develop a lower-cost, lower-height barrier capable of containing and redirecting a tractortank trailer vehicle at MASH TL-6 impact conditions.

This study describes Phase IV of a multi-year development effort sponsored by the Mid-America Transportation Center (MATC). A 62-in. tall, 5.5-degree single-slope median barrier was designed to withstand a 300-kip design lateral load. The barrier system was impacted by an 80,026-lb 2010 Columbia 112 Freightliner tractor and 1997 LBT tank trailer at a speed of 51.1 mph and an angle of 15.5 degrees. The barrier successfully contained and redirected the tractor-tank trailer without barrier penetration or override. Upon exit, the vehicle rolled 90 degrees and slid on the concrete tarmac through 6.5 seconds. The vehicle with ovalshaped tank and sloshing liquid cargo traversed the concrete tarmac and began to roll another 180 degrees, whereby crush occurred to the truck’s cab. Minimal damage occurred to the barrier system. Through 6.5 seconds, the MASH TL-6 barrier system contained and redirected the vehicle with roll onto its side and with all occupant risk criteria met. Further discussion is recommended to determine proper crash test expectations for TL-6 barriers under high-energy impact events with round-tank trailers.

This is the End of Year 4 project report. The End of Year 1, 2, and 3 reports can be found under the following report numbers:

TRP-03-404-18 - End of Year 1

TRP-03-430-20 - End of Year 2

TRP-03-457-21 - End of Year 3

KEYWORDS

MASH TL-6, Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH 2016, Single-Slope Barrier, Median Barrier

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