Magic Roundabout (Hemel Hempstead) Magic Roundabout (Hemel Hempstead) The "Magic Roundabout" in Hemel Hempstead, Hertfordshire, England, is the familiar name given to the Plough roundabout. The familiar name comes from the children's television programme, and is also used for a similar junction in Swindon and the M40 junction in Denham. The official name relates to a former public house, called "The Plough Inn", which was between the junction of what is now Selden Hill and St Albans Road. It has also been known as the Moor End Roundabout as it is adjacent to the part of Boxmoor nearest the town. Before Hemel Hempstead became
Roundabout roundabout arms perpendicularly, well outside the circle. A pedestrian island allows pedestrians and cyclists to cross one lane at a time. The capacity of a roundabout varies based on entry angle, lane width, and the number of entry and circulating lanes. As with other types of junctions, operational performance depends heavily on the flow volumes from various approaches. A single-lane roundabout can handle approximately 20,000–26,000 vehicles per day, while a two-lane design supports 40,000 to 50,000. Under many traffic conditions, a roundabout operates with less delay than signalised or all-way stop approaches. Roundabouts do not stop all entering vehicles, reducing