spiral

lemniscate

cubic parabola

any of the above

based on allowable rate of change of centrifugal acceleration

based on rate of change of superele-vation

higher of [a] and [b]

smaller of [a] and [b]

ruling gradient

limiting gradient

exceptional gradient

minimum gradient

0.10%

1%

10%

no compensation

3%

4%

5%

6%