Standard carriageway widths as per common IRC practice According to typical Indian Road Congress (IRC) guidelines, which of the following carriageway widths are correct?
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A3.75 m for a single-lane road
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B7.0 m for two lanes without raised kerbs
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C7.5 m for two lanes with raised kerbs
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D10.5 m for a three-lane pavement
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EAll the above
Answer
Correct Answer: All the above
Explanation
Introduction / Context:Carriageway width determines lane capacity, safety margins, and comfort. IRC standards provide typical widths by facility type and roadside elements (e.g., presence of raised kerbs).
Given Data / Assumptions:
- Standard two-way and multi-lane categories.
- Urban kerbed sections tend to be slightly wider than rural without kerbs.
Concept / Approach:Common IRC values include 3.75 m for single-lane, 7.0 m for two-lane without raised kerbs, 7.5 m for two-lane with raised kerbs, and 10.5 m for three-lane facilities. These provide adequate clearance and shy distances.
Step-by-Step Solution:
Check each item against the standard catalogue.All listed values match widely used IRC practice.Verification / Alternative check:Design manuals and typical cross-sections align with these nominal dimensions, subject to context-specific adjustments.
Why Other Options Are Wrong:Since A–D are each correct, “All the above” is the correct consolidated choice.
Common Pitfalls:Confusing carriageway width with roadway width (which adds shoulders and medians).
Final Answer:All the above