How to use a roundabout

[ScottRAB]

quote:

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Originally posted by pahoated

The flaw is a single lane roundabout. All the examples of roundabouts working are two lane which makes sense. A one lane roundabout means a bottle neck, if anything happens in it.

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No logic there.
Single-lane modern roundabouts (90-120 feet in diameter) can handle intersections that serve about 20,000 vehicles per day with peak-hour flows between 2,000 and 2,500 vehicles per hour. Two- and three-lane modern roundabouts (150-220 feet in diameter) can serve about 50,000 vehicles per day and handle 2,500 to 5,500 vehicles per hour. Right-turn slip lanes can increase those numbers if needed (just like for signal intersections). Much depends on how balanced the entries are, but only in determining how many lanes are needed for each movement.
Most crashes will be fender benders and you can use the truck apron to go around if they don't move off the circular roadway.