Medians – minimum desirable widths in practice Which of the following statements about median width provisions is correct for rural highways and long bridges/viaducts?
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AMinimum desirable width of medians on rural highways is about 5 m
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BMinimum width of medians should be about 3 m
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COn long bridges and viaducts, median width may be about 1.5 m
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DAll the above
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ENone of these
Answer
Correct Answer: All the above
Explanation
Introduction / Context:Medians separate opposing traffic streams, improve safety, and offer space for future lanes, lighting, and barriers. Practical widths vary with setting and structural constraints.
Given Data / Assumptions:
- Rural highway cross-sections versus constrained bridge decks.
- Use of raised/flush medians with or without barriers.
- Provision for drains, lighting, or future widening.
Concept / Approach:On rural highways, wider medians (≈ 5 m) enhance safety and flexibility. Where right-of-way is limited but separation is still necessary, a median as narrow as ≈ 3 m may be adopted. On long bridges/viaducts, structural economy and deck width limitations often restrict medians to ~1.5 m, sometimes replaced by barriers.
Step-by-Step Solution:
Relate function to context → open rural sections tolerate wider medians.Constrained structures → reduced medians with barriers are common.All statements reflect practical provisions at different constraints.Verification / Alternative check:Cross-section catalogues and bridge typical drawings commonly show ≈ 1.5 m deck medians and wider earthen medians on embankments matching these magnitudes.
Why Other Options Are Wrong:Since A–C each apply in their respective contexts, the only fully correct choice is All the above.
Common Pitfalls:Assuming a single median width fits all; forgetting barrier and shy distance requirements on narrow medians.
Final Answer:All the above