Cross slope 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 drainage gradient so that water will run off the surface to a drainage system such as a street gutter or ditch. Inadequate cross slope will contribute to aquaplaning. On straight sections of normal two lane roads, the pavement cross section is usually highest in the centre and drains to both sides. In horizontal curves, the cross slope is banked into superelevation to reduce steering effort and lateral force required to go around the curve. All water drains to the inside of the curve. If the cross slope magnitude oscillates within 1 - 25 metres, the body and payload of high (heavy) vehicles will experience high roll vibration.
Cross slope is usually expressed as a percentage: Cross slope .
Typical values range from 2% for straight segments to 10% 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).
Famous quotes containing the word cross:
“In ancient times—’twas no great loss—
They hung the thief upon the cross:
But now, alas!—I say’t with grief—
They hang the cross upon the thief.”
—Anonymous. “On a Nomination to the Legion of Honour,” from Aubrey Stewart’s English Epigrams and Epitaphs (1897)