Gradient : is the rate of rise or fall along the length of the road with respect to the horizontal.

Types. 1) Ruling Gradient 2) Limiting Gradient 3) Exceptional gradient 4) Minimum gradient

Ruling Gradient: is the maximum gradient within which the designer attempts to design the vertical profile of a road. This are adopted as a normal cause in design of vertical alignment. The selection of ruling gradient for the purpose of design is a complex job as several Factor such as type of terrain, the length of the grade, the speed pulling power of different types of vehicles and presence of horizontal curves are to be considered.

Limiting Gradient: where topography of a place compels adopting steeper gradient than the ruling gradient, limiting gradient is used in view of enormous increase in cost in construction roads with gentle gradients

Minimum gradient :This is important only at locations where surface drainage is important. Camber will take care of the lateral drainage. But the longitudinal drainage along the side drains require some slope for smooth flow of water. Therefore minimum gradient is provided for drainage purpose and it depends on the rain fall, type of soil and other site conditions.

Exceptional gradient : Exceptional gradient are very steeper gradients given at unavoidable situations. They should be limited for short stretches not exceeding about 100 metres at a stretch. In mountainous and steep terrain, successive exceptional gradients must be separated by a minimum 100 metre length gentler gradient. At hairpin bends, the gradient is restricted to 2.5