Describe the special considerations for aligning roads on hilly areas- Hilly road alignment and describe.

Alignment through hilly areas is different from the flat terrain. For the purpose of efficient and safe operation of vehicles through a hilly terrain special care should be taken while aligning the highway.

• Stability of the slops:

For hilly areas, the road should be aligned through the side of the hill that is stable. The common problem with hilly areas is that of landslides. Excessive cutting and filling for road constructions give way to steepening of slopes which in turn affect the stability.

• Hillside drainage:

Adequate drainage facility should be provided across the road. Attempts should be made to align the roads in such a way where the number of cross drainage structures required are minimum, which reduce the construction cost.

• Special geometric standards:

The standards followed in hilly areas are different. The alignment chosen should enable the ruling gradient to be attained in a minimum of the length, minimizing steep gradient, and hairpin bends and needless rise and fall.

• Ineffective rise and fall:

Efforts should be made to keep the ineffective rise and excessive fall minimum.