Sight Distance MCQ with answer and solution

Concept

Stopping Sight Distance vs Decision Sight Distance

Formula

SSD = v·t + v² / (2·g·f) where: - v = speed of vehicle - t = perception-reaction time - g = acceleration due to gravity - f = coefficient of longitudinal friction

Step-by-step solution

- Identify the condition: Stopping Sight Distance (SSD) accounts for standard driver perception-reaction time and braking distance under normal conditions. - Compare with complex situations: Complex traffic conditions require additional decision-making time, which requires Decision Sight Distance (DSD) rather than standard SSD. - Select the correct option: Since SSD applies only to normal conditions, option (a) "Only (i)" is correct.

Explanation

Stopping sight distance (SSD) is designed to allow a driver to safely stop under normal traffic conditions. For complex situations that require extra reaction time or decision-making, a longer distance known as decision sight distance is required.

Shortcut

SSD is for Normal conditions; Decision Sight Distance (DSD) is for Complex situations. Remember: SSD = Simple/Standard, DSD = Decision/Difficult.

Common mistake

Many students select Option B "(i) and (ii)" because they assume Stopping Sight Distance (SSD) applies universally to all driving scenarios, confusing standard SSD with Decision Sight Distance (DSD), which is required for complex or unexpected situations.