A vertical curve is designed on the basis of the
- Aradius of the curve
- Bminimum sight distanceCorrect
- Cchange of gradient
- Dall of the above
Solution
Concept
Design criteria for highway vertical curves
Formula
NONE
Step-by-step solution
1. Vertical curves are provided on roads and railways to connect intersecting grade lines smoothly. 2. The design length of summit vertical curves is governed primarily by required sight distances. 3. Ensuring minimum sight distance allows drivers to safely stop or overtake when navigating grade changes. Answer: B
Explanation
Vertical curves on roads provide a smooth transition between different gradient slopes. The governing criteria for determining their length and profile is ensuring adequate sight distance for driver safety, such me stopping sight distance. Meeting sight distance requirements ensures drivers have enough visible distance to react to obstacles on the road ahead.
Why the other options are wrong
A) Curve radius alone does not determine vertical curve length, which relies on sight distance requirements. C) Change of gradient is used in the calculation, but safety sight distance governs the minimum length design. D) Vertical curve design primarily depends on driver visibility and minimum sight distance.
Shortcut
Vertical curve design considers both change of gradient and minimum sight distance.
Common mistake
Choosing "all of the above" instead of recognizing minimum sight distance as the primary basis for vertical curve design.
Correct answer: B) minimum sight distance