Roundabouts work well to reduce waiting time vis-a-vis a traffic light. However each roundabout will have a capacity limit beyond which they lose their purpose and instead cause endless chaos. This limit is dependent on the number of vehicles expected and the diameter of the roundabout. Roundabouts on corniche at peak hours are prime examples where they have crossed capacity and are thus redundant.
(Qatarisun, to answer your question,) when this happens, the options then are
1. Resort to traffic lights
2. Increase diameters (Usually impractical)
3. Build flyovers / underpasses. (Expensive)
4. Make one-ways. (You need alternative routes for the other corresponding one-way
5. Or some others that dont come to mind.
So now if you want to install a set of lights (cheapest option), you can either do it WITH the central circle being left there as it is or by removing the circle. Removing a circle means labourers breaking it down and then a road (asphalting or cementing as applicable) being made over that place. For all this, the road will have to be decommissioned for some time while these works are being carried out. Hence the roundabouts will remain.
"The power of accurate observation is commonly called cynicism by those who have not got it"
Roundabouts work well to reduce waiting time vis-a-vis a traffic light. However each roundabout will have a capacity limit beyond which they lose their purpose and instead cause endless chaos. This limit is dependent on the number of vehicles expected and the diameter of the roundabout. Roundabouts on corniche at peak hours are prime examples where they have crossed capacity and are thus redundant.
(Qatarisun, to answer your question,) when this happens, the options then are
1. Resort to traffic lights
2. Increase diameters (Usually impractical)
3. Build flyovers / underpasses. (Expensive)
4. Make one-ways. (You need alternative routes for the other corresponding one-way
5. Or some others that dont come to mind.
So now if you want to install a set of lights (cheapest option), you can either do it WITH the central circle being left there as it is or by removing the circle. Removing a circle means labourers breaking it down and then a road (asphalting or cementing as applicable) being made over that place. For all this, the road will have to be decommissioned for some time while these works are being carried out. Hence the roundabouts will remain.
"The power of accurate observation is commonly called cynicism by those who have not got it"