IRC dimensions – single-lane National Highway in hilly terrain (IRC:52-1973) For a single-lane National Highway located in hilly regions, what set of standard dimensions is recommended for carriageway width, shoulder width (each side), and total roadway width?

Introduction / Context:
Geometric standards by the Indian Roads Congress (IRC) specify minimum widths to ensure safe operations, even on constrained hilly terrains. A single-lane road still requires adequate shoulder space for lateral support, drainage, and emergency stops.

Given Data / Assumptions:

• Single-lane National Highway in hilly region.
• Traditional IRC recommendations are referenced.
• We compare carriageway, shoulder, and total roadway widths.

Concept / Approach:
Carriageway width provides the traffic lane, while shoulders improve structural support and safety. In hilly terrain, the total roadway includes the paved lane plus shoulders, often slightly reduced compared to plains due to topographic constraints, yet maintaining basic safety margins.

Step-by-Step Solution:

Verification / Alternative check:
These values align with long-standing IRC tabulations for hilly regions and appear in typical state PWD schedules for single-lane hill roads.

Why Other Options Are Wrong:
Options listing any one value alone are incomplete; the question seeks the full set recommended for the section type.

Common Pitfalls:
Confusing total roadway with formation width; omitting shoulder widths on hill roads due to terrain pressure, which compromises safety.

Final Answer:
All of the above