Question

Which of the following is a limitation of traffic rotary?
1. All traffic including those turning right or straight have equal opportunity as those turning left
2. When the distance between intersections on an important highway is less, rotaries become troublesome.
3. Capacity of rotary intersection is the highest of all other intersection at grade
4. Rotaries can be constructed with advantage when the number of intersecting roads is between four and seven

Answer 1

Correct Answer - Option 2 : When the distance between intersections on an important highway is less, rotaries become troublesome.

Explanation:

Traffic rotary:

Traffic Rotary at road intersections is a special form of grade change of lanes to channelize the movement of vehicles in one direction around a central traffic island. With the rapid growth of traffic, it is experienced the widening of roads, and providing flyovers have become imperative to overcome major conflicts at intersections such as the collision between through and right-turn movements. In this way, major conflicts are converted into milder conflicts like merging and diverging. The vehicles entering the rotary are gently forced to move in a clockwise direction.

Limitation of the traffic rotary:

• The maximum traffic which a rotary can efficiently handle is 3000 vehicle/hour and a minimum of 500 vehicle/hour.
• Design speed is 40 km/hour for rural areas and 30 km/hr for urban areas.
• Entry to the rotary is never made straight, small curvature is always introduced to forcefully reduce the speed of the vehicle.
• Superelevation in a rotary is provided equally to the camber of the road.
• When the distance between intersections on an important highway is less, rotaries become troublesome.