Geometric Design MCQ with answer and solution

Concept

Summit Curves

Formula

No formula needed.

Step-by-step solution

1. Identify that transition curves are used in horizontal alignment to gradually introduce centrifugal force. 2. Recognize that for summit curves (vertical alignment), centrifugal force acts vertically upward, making transition curves unnecessary. 3. Select Option C (Transition curve) as the curve that should not be used.

Explanation

Transition curves are designed to gradually introduce centrifugal force, which is necessary for horizontal curves to prevent sudden side discomfort. However, on summit curves, centrifugal force acts vertically upwards (opposing gravity), so comfort is not an issue. Therefore, transition curves are unnecessary and not used for summit curves; simple parabolic curves are preferred instead.

Shortcut

Remember: Summit curves are vertical alignment curves, while Transition curves are strictly designed for horizontal curves to handle lateral centrifugal force. Thus, Transition curves are never used on summit curves.

Common mistake

Many students confuse summit curves (vertical alignment) with horizontal curves and incorrectly choose parabolic or circular curves, forgetting that transition curves are designed strictly for horizontal alignment to introduce centrifugal acceleration gradually and are never required on summit curves.