A transition curve should satisfy which of the following conditions? 1. It should meet the straight line part of the road tangentially 2. The length of it must be such that the cant or superelevation can be provided conveniently to its maximum value at the beginning of the circular curve 3. The rate of increase of the curvature should be such that it matches with the rate of increase of cant Select the correct answer.
- A1 and 2 only
- B1 and 3 only
- C2 and 3 only
- D1, 2 and 3Correct
Solution
Concept
Conditions to be satisfied by a transition curve
Step-by-step solution
1. It must be tangential to the straight at its start (statement 1). 2. Its length must let the full superelevation be attained by the beginning of the circular curve (statement 2). 3. The rate of change of curvature should match the rate of increase of cant (statement 3).
Explanation
These are the three classic requirements of a transition curve.
Why the other options are wrong
Each of the other options leaves out one valid condition.
Shortcut
Tangential, cant attained, curvature rate = cant rate.
Common mistake
Dropping one condition.
Correct answer: D) 1, 2 and 3