Terminology of longitudinal slope on highways If the elevations along a road increase in the direction of travel, the longitudinal slope is called:
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Agradient
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Bgrade
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Cpositive grade
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Dnegative grade
Answer
Correct Answer: positive grade
Explanation
Introduction / Context:Road longitudinal profiles are described using grades. Positive grades climb with chainage; negative grades descend. Clear terminology assists in drainage and capacity calculations.
Given Data / Assumptions:
- Elevation increases with distance along the alignment.
- Direction of travel coincides with increasing chainage.
Concept / Approach:A “grade” is the longitudinal slope, expressed as a percentage or 1 in S. When the roadway rises in the travel direction, it is a positive grade; when it falls, it is a negative grade.
Step-by-Step Solution:
Check elevation trend → increasing with chainage.Therefore classify as “positive grade”.Verification / Alternative check:Design drawings typically annotate +g for upgrades and −g for downgrades; drainage inlets and climbing lane needs are based on these signs.
Why Other Options Are Wrong:“Gradient/grade” are generic terms; “negative grade” is the opposite case.
Common Pitfalls:Mixing sign conventions when local coordinates are reversed; not distinguishing algebraic sum for vertical curves.
Final Answer:positive grade