A circle route, circle line, or circumference route, in a public transport network or system, is a route following a path approximating a circle, or at least a closed curve. Such a route may be operated by various forms of public transport.
The expression "circle route" may refer in particular to:
- a route orbiting a central point, commonly the central business district (CBD), in a city or town
- a route running in approximately a circular path from a point near the centre of a city or town out to a peripheral point and back again
- a feeder route running from an interchange station around a neighbourhood or suburb in approximately a circle
Typically, a circle route will connect at several locations with one or more cross-city routes or radial routes offering services in a straighter line into or out of a city or town centre. When a circle route orbits a central business district in a large arc, it will often provide transverse (or lateral) links between suburbs or satellites, either on its own or in combination with other routes. Such connections assist travellers by reducing travel times, avoiding congested centres, and sometimes reducing the number of transfers. Similar benefits may also be achieved by half-circle routes or peripheral cross-city routes.
The oldest circular rapid transit line was London's Inner Circle, today the Circle line of the London Underground, which was completed in 1884, operated by two separate companies. The route chosen forms the general border of what is today central London. This was followed by the Glasgow Subway which opened in 1896, with the system unchanged to this day. Most recently, the line 3 of the Copenhagen Metro opened, connecting running through the city centre and out to the north and eastern suburbs. In some cities such as Paris, where lines 2 and 6 encircle the city, multiple services together can effectively form a circular route.
- "How old is the Circle line?". The Telegraph. Telegraph Media Group. 6 October 2016. Retrieved 13 October 2019.
- metrobits.org: Metro Rings and Loops – includes a list of commuter rail and rapid transit circle routes worldwide