Demand responsive transport

Demand-responsive transport, also known as demand-responsive transit (DRT), demand-responsive service, 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 special needs 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.

Differences from other modes of transport

 * Regular transit bus routes: DRT employs flexible routes and schedules
 * Shuttle bus services: DRT departure and arrival points are not necessarily fixed
 * Deviated Fixed Route Service: Transit service that operates along a fixed alignment or path at generally fixed times, but may deviate from the route alignment to collect or drop off passengers who have requested the deviation
 * Paratransit: DRT is available to the general public, whereas paratransit is available to pre-qualified user bases, especially for people with disabilities and the elderly
 * Share taxis: DRT is pre-booked in advance, whereas share taxis are operated on an ad-hoc basis
 * Taxicabs: DRT generally carries more people, and passengers may have less control over their journey on the principle of DRT being a shared system as opposed to an exclusive vehicle for hire. Additionally, journeys may divert en route for new bookings.

Mode of operation
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.

DRT systems take advantage of fleet telematics technology in the form of vehicle location systems, scheduling and dispatching software and hand-held/in vehicle computing.

Vehicles used for DRT services will usually be small minibuses, reflecting the low ridership, but also allowing the service to provide as near a door to door service as practical, by being able to use residential streets. In some cases Taxicabs are hired by the DRT provider to serve their routes on request.

Simulations of health and environmental effects
For a model of a hypothetical large-scale demand-responsive public transport system for the Helsinki metropolitan area, simulation results published in 2005 demonstrated that “in an urban area with one million inhabitants, trip aggregation could reduce the health, environmental, and other detrimental impacts of car traffic typically by 50–70%, and if implemented could attract about half of the car passengers, and within a broad operational range would require no public subsidies”.

Licensing
DRT schemes may require new or amended legislation, or special dispensation to operate, as they do not meet the traditional licensing model of authorised bus transport providers or taxicab operators. The status has caused controversy between the bus and taxi operators when the DRT service picks up passengers without pre-booking, due to the licensing issues.

List of routes under the scheme

 * Tampines Block 123 - Suntec City - Esplanade - Orchard Road (Loop)
 * Tampines Block 123 - Suntec City - Bugis - Little India - Kampong Glam - City Hall - Chinatown - Parliament Place (Loop)
 * Tampines Block 123 - Suntec City - Marina Bay - VivoCity - Sentosa
 * Service 28:
 * Service 72: Tampines - Yio Chu Kang skipping any stop
 * Service 147:
 * Service 190: