Guernsey is the second largest of the Channel Islands. It is part of the Common Travel Area, allowing passport-free travel to and from the United Kingdom or Jersey. Travel to and from mainland Europe requires a passport or an EU national identity document. Non EU citizens may need a visa. Bus services are operated by CT Plus Guernsey on behalf of the Environment Department of the States of Guernsey (the island’s government). Vehicles used are based on buses used in the UK but with a slightly narrower construction, to allow them to circulate on the island's narrow roads, legal limit 2.31 metres (7' 6¾"). A number of narrower (and shorter) StreetVibe buses will be on the roads from May 2017. Guernsey has a regulated, licensed taxi service based at three ranks in central St Peter Port, St Sampson's (at 'The Bridge') and at Guernsey Airport. Taxis can also be called or phoned. Accessible taxis capable of transporting a wheelchair passenger and with improved lighting to assist people who may have a visual impairment are available. Visit Guernsey website has a list of taxi operators.