The British love their roundabouts.
The first British roundabout was in Letchworth Garden City in 1909; it was originally intended partly as a traffic island for pedestrians. Research has shown that roundabouts are much safer than road junctions. Accident rates have greatly reduced where roundabouts have replaced junctions or intersections. Roundabouts are often placed in city centres as an alternative to large traffic light intersections. They are most commonly used on dual carriageways as a means of controlling traffic and thus reducing speed.
Research has shown that many people don’t understand roundabouts. Many drivers don’t know how to position their car correctly when approaching or travelling around the roundabout. Some are unaware of how to signal properly when joining or when exiting roundabouts. Therefore, drivers need to be cautious when other cars on the roundabout are signalling. For example, if a car is indicating left it may not mean the driver is taking the first exit off the roundabout; he may in fact have signalled too early and actually wants to come off the next exit straight on his left.
Roundabouts may be safer than junctions but concentration and extreme caution is advised when using roundabouts. Keep well back from the car in front to avoid the “roundabout shunt.” [from Road Driver at https://www.roaddriver.co.uk/safety-tips/how-to-navigate-roundabouts/. note: shunt = motor accident]
Here is a helpful visual to assist in roundabout etiquette (look carefully and you can see they have included the directional signal and where it is to be engaged):
This is a picture of what is reputed to be the most difficult roundabout in Britain to navigate. It is in the town of Swindon and is referred to it as Swindon’s Magic Roundabout.
We have roundabouts in the USA, but we call them a variety of different things, depending on the region. In New England they are called rotaries; in New York they are Traffic Circles (according to BBC America, In 2013 the British Roundabout Appreciation Society awarded Columbus Circle, in New York City, Best Roundabout in the World.)
And in other places they are actually called roundabouts. The rules seem to be simpler though–traffic in the roundabout has priority, and there is usually only one lane. And they are not part of any driving test!!