Definition of superelevation in US English:

superelevation

noun

  • The amount by which the outer edge of a curve on a road or railroad is banked above the inner edge.

    • ‘The LC.C. Accident Report assigns the accident to excessive speed on the curve, which had a limit of 20 mph, since it was a 12-1/2 degree curve with only three inches of superelevation.’
    • ‘Okay, the superelevation wasn't that steep, but still…’
    • ‘Mr Gallagher, who is an experienced road construction supervisor, also highlighted a deficiency in the superelevation of the road (agreed by the council) at the site of the crash scene.’

Pronunciation

superelevation

/ˌso͞opərˌeləˈvāSH(ə)n/