Many people ask why not build it straight up to save costs

Most of us understand that the shortest line is a straight line connecting two places. However, this approach is not followed while building roads up mountains or steep slopes. If you get the opportunity to visit the mountainous areas, you will see meandering roads like these.

Some routes leading up the mountain have even become famous across the world due to their twisting and many twists. So, why don’t they create these roads in a straight line rather than zigzag?

The solution is simple: it protects pedestrians’ lives by making it easier for them to walk up hills. In the past, while building a road to the top of a mountain, people would typically bring a donkey and let it climb the slope to investigate first.

They discovered that this animal did not choose the shortest straight path, but rather a path with a slight incline. Because this is the slope where they feel comfortable (approximately 8 to 10 degrees). The exploration team will create based on the animal’s route, after measuring and sketching it.

In terms of science, the reasoning is as follows. Long periods of running uphill in a straight path might impair drivers’ vision. This may easily lead to distraction and danger. Curvy and twisting roads will help drivers concentrate more.

Some Special Features of Hill Roads are the following:

-Hill road should be aligned along the stable side of the gill slope to forestall land-slides.

-Existence of the quantity of hair-pin bands, sharp horizontal curves.

-Construction of efficient surface and sub-surface drainage.

-Existence of huge numbers of cross-drainage structures like bridges and culverts.

Alignment of hill road:

The main factors to be considered while deciding the alignment of hill roads are as discussed.

Length:
The cost of a hill road per kilometer length is relatively very high. It should therefore be ensured that the length of the road connecting two stations should be minimum possible, adopting ruling gradients along most of the length.

Altitude of the road:
At lower altitudes, large numbers of cross drainage works are required to be constructed. Whereas at higher altitudes, the road pavement may witness snowfall during winter. this is often why the alignment of hill roads should well be provided at an altitude between 900 m slopes exposed to sum. the Hill slopes which are subjected to high winds should never be selected unless and until there’s no other alternative. within the hemisphere, the hills’ southern
slopes are more suitable than the northern slopes, which remain tin shades and are usually subjected to high winds.

Saddles or Passes:
While locating the con-tour gradient of the proposed alignment of a hill road on a contour map, it should cross the ranges through saddles. Through the length of the road is increased, the heavy cost of cutting through rocks is avoided. due to increased length, ruling gradients will be suitably adjusted.

Stability of hill slopes: 

While deciding the alignment of hill roads, it should be ensured that the slops are stable and not very steep. the area isn’t prone to landslides and settlements. This factor is of special importance in hills having sedimentary rocks.

Geological structure:
Cutting through solid hard rocks is extremely expensive. The alignment of roads is also suitably deviated to avoid such areas.

Tunnels:
Drilling tunnels are incredibly expensive. The long tunnels need ventilation moreover as a lighting arrangement. As far as possible, tunnels should be avoided and resorted to given that another suitable alternative isn’t feasible.

Valleys:
While deciding the alignment for crossing a river valley, due consideration should lean to avoid the con-striation of several bridges on its tributaries.

Camping sites:
At an intermittent distance, the alignment of the Hill road should pass through gentle slopes where suitable camping sites may be developed for military personal just in the case essentially.

Maintenance problems fully hill roads

-Hill Roads are mostly in cutting. Breast walls are provided to avoid erosion of soil which takes place when slops in cutting are steep.

-Serious erosion takes place when the slopes are steep and the top bare.

-Catch water drains are provided to drain away water from upper regions.

-Freshly cut areas disturb the stability of the cut portion.

-The cut portion bulges out under the action of water.