Cross slope
Cross slope, cross fall or camber is a geometric feature of pavement surfaces: the transverse slope with respect to the horizon. It is a very important safety factor. Cross slope is provided to provide a
superelevation to reduce steering effort and lateral force required to go around the curve.[1] All water drains to the inside of the curve.[2]
If the cross slope magnitude oscillates within 1–25 metres (3–82 ft), the body and payload of high (heavy) vehicles will experience high roll vibration.
Cross slope is usually expressed as a percentage:
- .
Cross slope is the angle around a vertical axis between:
- the horizontal line that is perpendicular to the road's center line, and
- the surface.
Typical values range from 2 percent for straight segments to 10 percent for sharp superelevated curves. It may also be expressed as a fraction of an inch in rise over a one-foot run (e.g. 1⁄4 inch per foot).
See also
- Camber angle
- Cant (road/rail)
- Geometric design of roads
References
- ^ Department of Transportation (23 January 2023). "Superelevation Design Guide" (PDF).
- ^ WSDOT (23 January 2023). "Cross Slope and Superelevation" (PDF).