Analysis of Solutions for Superelevation Design from the Standpoint of Efficient Drainage

Martina Zagvozda, Željko Korlaet

Last modified: 2017-02-28


The determination of pavement cross slope is integral part of geometric design of roads. It is performed due to reasons of driving dynamics i.e. to ensure lateral stability of vehicle in a curve and also to assure optimal drainage of pavement. Empirical knowledge, incorporated in guidelines for road design in many countries, indicate that the minimum value of cross slope to ensure sufficient drainage is 2.5%, which is also common value on the tangent parts of the road. The problem occurs on parts of the route between the opposite curves in which, due to the need for change in cross slope direction, the cross slope ranges from 0-2.5%. A particular problem occurs on parts of the route with (too) small longitudinal gradient, which does not ensure efficient drainage in the longitudinal direction. The subject of this paper is analysis of options for superelevation design in a number of countries (CRO, D, A, CH, UK, USA, AUS), and a critical comparison of available solutions, considering the criteria of efficiency or optimization of pavement drainage.


superelevation; geometric design; sufficient drainage

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