Geometric Design MCQ with answer and solution

Concept

Exceptional Gradient in Mountainous Terrain

Formula

No formula; this is a standard specified by the Indian Road Congress (IRC) guidelines.

Step-by-step solution

Recall the IRC guidelines for exceptional gradient in mountainous terrain (1 in 14.3 or 7%) and select Option C.

Explanation

As per the Indian Road Congress (IRC) guidelines, the exceptional gradient for roads in mountainous terrain is recommended as 1 in 14.3 (or 7%). This steep gradient is allowed only in extreme conditions for very short stretches (up to 100 meters) when gentler slopes are not feasible due to difficult topography.

Shortcut

Remember "7% in 14.3" by doubling 7 to 14 and adding .3 (7 × 2 = 14 → 1 in 14.3).

Common mistake

Students often confuse the exceptional gradient (1 in 14.3) with the ruling gradient (1 in 20) or limiting gradient (1 in 15) for mountainous terrain.