What point must be kept in mind while aligning road in hilly area

Special attention must be paid to the following aspects of hill roads when they are being aligned:
1. Hill slope stability
2. Surface and subsurface water drainage from the hillside
3. Resisting length and
4. Special geometric standards for hill roads

Stability

The road on the slope’s stable side should be aligned with particular care. Landslides are a common concern along hill roads. Cutting and filling soil to build roads on a hillside causes existing slopes to steepen, compromising the hillside’s stability.

Drainage

Ample drainage over the road was supplied by numerous hillside drains. Due to the high cost of cross-drainage structures, efforts should be made to align the road such that the number of extremely expensive cross-drainage structures is kept to a minimum.

Geometric standard

On hill roads, different geometric standards apply in terms of gradient, curves, and speed, and these standards determine sight distance, curve radius, and other associated factors. The route should allow for the majority of the distance to be covered at the ruling gradient, with high gradients, hairpin bends, and superfluous climbs and descents avoided.

Resisting length

The overall labor to transport the loads along the route taking the horizontal length, the actual difference in levels between the two stations, and the sum of ineffective rise and fall in excess of floating alignment can all be used to compute the resisting length of a road. In conclusion, the resistive length of the alignment should be kept as small as possible. As a result, inefficient rises and falls should be maintained to a minimum.