Minimum Stopping Sight Distance for Two Lane, Two Way Traffic

Stopping distance and stopping sight distance are two different terms in transportation engineering. Stopping distance is the distance required to stop a vehicle after the brake is applied. Stopping sight distance is the distance a driver needs to see in order to safely stop their vehicle before hitting any obstacle or other vehicles in the roadway.

Given that the stopping distance is 60 metres, the minimum stopping sight distance for two lane, two way traffic is 60 meters. This means that a driver must be able to see at least 60 meters ahead in order to be able to stop their vehicle safely.

Explanation

The minimum stopping sight distance is calculated based on the following factors:

1. Perception time: The time it takes for a driver to recognize a hazard and react to it. This is typically 1.5 seconds.

2. Reaction time: The time it takes for a driver to apply the brakes after recognizing a hazard. This is typically 1.5 seconds.

3. Braking distance: The distance a vehicle travels while braking. This is dependent on the vehicle speed, road conditions, and vehicle condition.

The formula for calculating stopping sight distance is:

SSD = Perception distance + Reaction distance + Braking distance

Where:

Perception distance = Perception time x Speed

Reaction distance = Reaction time x Speed

Braking distance = (Speed^2) / (2 x deceleration)

Deceleration = (Braking efficiency x Gravity)

Given the stopping distance of 60 metres, we can assume that the vehicle was traveling at a certain speed when the brakes were applied. Using the above formula, we can calculate the minimum stopping sight distance required for that speed.

In this case, since the stopping distance is equal to the minimum stopping sight distance, we can assume that the vehicle was traveling at the maximum allowable speed for that road section. Therefore, the minimum stopping sight distance for two lane, two way traffic is 60 meters.