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When contractors are slip-forming concrete barrier on a super elevated section of road, are the contractors installing the concrete barrier perpendicular to the super elevation, or are they installing the barrier plumb (i.e. perpendicular to center of the earth)?

I'm trying to get an idea of the state of practice in other states, so whatever assistance you could provide would be greatly appreciated.

When a barrier is installed on the inside of a super elevated section, constructing the barrier vertically is probably the safest alternative.  The problem with using a vertical barrier only develops when the barrier is installed on the outside of the super.  In this situation, the vehicle has a significant upward velocity as it travels up the superelevated cross-section.  When a vehicle that is already traveling upward strikes a safety shape, the propensity for climbing is dramatically increased.  Hence, there is concern about using a vertical safety shape on the outside of a steeply superelevated curve.