Magic Roundabout (Hemel Hempstead) viaduct. The BP building was found to be unstable due to defective reinforced concrete and the exit had to be closed. The building was demolished but the original route was not restored, although a newer side exit from the roundabout replaced the junction with Marlowes off a side road. 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
Roundabout of the first American roundabouts for both autos and streetcars (trams) in the Hanchett Residence Park in what is now San Jose, California. The first British circular junction was built in Letchworth Garden City in 1909. Its centre originally was intended partly as a traffic island for pedestrians. It was featured in the film "The World's End". In the early 20th century, numerous traffic circles were constructed in the United States, particularly in the northeast. Examples include a circle in Atherton, California. Widespread use of the modern roundabout began when the UK's Transport Research Laboratory engineers re-engineered and standardised circular