Dial-a-ride

Demand Responsive Transport or Demand-Responsive Transit (DRT) or Demand Responsive Service or Dial-a-Ride Transit (DART) or Flexible Transport Services is "an advanced, user-oriented form of public transport characterised by flexible routing and scheduling of small/medium vehicles operating in shared-ride mode between pick-up and drop-off locations according to passengers needs".

DRT systems typically provide a public transport service for areas of low passenger demand, such as rural areas, where a regular bus service would not be viable. DRT services may also be provided especially for disabled passengers, as with paratransit programs. Ridership on DRT services is usually quite low (less than ten passengers per hour), but DRT can provide coverage effectively.

DRT schemes may be fully or partially funded by the local transit authority, as providers of socially necessary transport. As such, operators of DRT schemes may be selected by public tendering. Other schemes may be partially or fully self-funded as community centred not for profit social enterprises (such as a Community interest company in the UK).

DRT schemes may also be provided by private companies for commercial reasons; some conventional bus operating companies have set up DRT-style airport bus services, which compete with larger private hire airport shuttle companies.

A DRT service will be restricted to a defined operating zone, within which journeys must start and finish. Journeys may be completely free form, or accommodated onto skeleton routes and schedules, varied as required. As such, users will be given a specified pick-up point and a time window for collection. Some DRT systems may have defined termini, at one or both ends of a route, such as an urban centre, airport or transport interchange, for onward connections.

DRT systems require passengers to request a journey by booking with a central dispatcher who determines the journey options available given the users' location and destination.

...
Wikipedia