9.2.10 Superelevation Transition

Desirable design values for length of superelevation transition are based on a given maximum relative gradient between profiles of the edge of traveled way and the axis of rotation.
Table 9-7
shows recommended maximum relative gradient values. Transition length on this basis is directly proportional to the total superelevation, which is the product of the lane width and the change in the cross slope. For superelevation on bridge structures, it is preferred to begin/end superelevation transition at a bridge bent line.
Table 9-7: Maximum Relative gradient for Superelevation Transition
Design Speed (mph)
Maximum Relative Gradient, %
1
Equivalent Maximum Relative Slope (V:H)
85-100
0.50
1:200
Notes:
Maximum relative gradient for profile between edge of traveled way and axis of rotation.