Magic Roundabout (Hemel Hempstead) a New Town the roads met in a simple junction which was then replaced by a standard roundabout. Constructed in 1973, the "Magic Roundabout" in Hemel Hempstead was voted the UK's second-worst roundabout in a 2005 poll held by an insurance company (the winner being its Swindon counterpart). In 2011 the roundabout was voted the best in Britain by motorists in a competition organised by a car leasing service. The original magic roundabout had six exits in total, with the British Petroleum building spanning "Marlowes", the road leading to the town centre, in the approximate position of the earlier railway
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