MASH Allowable Flare Rates for Portable Single-Slope Concrete Barriers

Portable concrete barriers (PCBs) are commonly used to provide positive protection in work zones. They also shield work-zone personnel from errant motorists when activities are being performed near the edge of the roadway. The exposed ends of PCBs can pose a hazard to motorists if left untreated. A common practice is to install a suitable crash attenuator at the end of the barrier to mitigate this hazard. However, this solution can be costly and time-consuming. When space permits, an alternative is to flare the PCB away from traffic to a point where the exposed end is outside the clear zone for adjacent traffic. Currently, limited guidance exists on the acceptable flare rate for PCBs under the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) 2016 guidelines. This paper evaluates the flare rate of the Texas Department of Transportation’s (DOT) freestanding 42-in. single-slope PCB through finite element (FE) analysis and crash testing according to the safety-performance criteria included in MASH. The flared single-slope PCB met the performance criteria for MASH Test Level 3 (TL-3) longitudinal barriers according to the implementation guidance provided.