If a stiffer/higher containment section of barrier system is required, a tested and accepted transition to Thrie beam, or another higher containment system, will reduce the risk of the barrier failing, or worse, the barrier spearing an errant vehicle.  

This short section of top rail we found on the Monaro Highway will be ineffective at providing increased containment (due to its short length), and it presents a spearing hazard to a vehicle that collides upstream of the secondary rail.