On-demand public transport
On-demand public transport, or demand responsive transport (DRT), is bookable public transport. It can replace the need to run a traditional fixed route and timetable, particularly during periods of low demand. DRT can replace existing routes or service previously unserved areas. Service models can vary from door-to-door transfers, to set or variable pick-up points, or be a mixture of these options.
The overall impact of on-demand public transport on CO2 emissions depends on the context in which the services are offered.
If new routes are introduced to previously unserved areas, emissions could increase due to the presence of new vehicles on the road. However, if on-demand transport causes modal shift from private cars, taxis, ridesourcing or other less sustainable modes, CO2 emissions will go down. The more responsive and convenient nature of the on-demand service suggests that it has the potential to increase public transport’s modal share, and thus achieve this goal.
While on-demand public transport is an emerging transport option, there is already some evidence for potential to reduce CO2 emissions. For example, a study of a DRT pilot programmes in 2019 in Finland showed a 12.6% reduction in vehicle-kilometres travelled. Although proportionate CO2 savings were lower, due to the fact that mini-busses replaced cars, a total savings of 2.6 tonnes of CO2 was recorded[i]. ITF simulations suggest that significantly larger proportionate gains are possible, estimating 28% and 62% CO2 reductions for the Helsinki and the Lisbon metropolitan areas respectively, if shared mobility is integrated into existing public transport services and all private vehicle travel is replaced.
[i] Estimated by the LIPASTO unit emissions database, see http://lipasto.vtt.fi/yksikkopaastot/indexe.htm (accessed 11 November 2021), based on CO2 emissions of 168 g/km for a passenger car (2016, urban driving) and 278 g/km for a minibus (6 tonne delivery lorry, empty, urban driving, EURO VI). Note, DRT pilot also included a mobile application and integration of services.
The cost of implementing DRT depends on a range of factors, including frequency of service, hours of operation, fares policy and fleet size. Some evidence suggests that, in addition to improving accessibility, DRT can yield cost savings when replacing existing fixed routes. For example, a number of Danish municipalities were able to combine subsidised services and replace unviable fixed lines with a single DRT service, achieving cost savings of around 20-40% (Lynott 2019a).
Other experiences show that DRT services can be very costly. For example, a DRT programme in rural New South Wales recorded an average cost per trip of AUD180 (June 2018) and farebox recovery of 3%, compared to 24% for fixed-route services in its first year of operation (Nelson and Wright 2021). Subsidies of up to EUR20 – 25 per trip have also been reported for DRT operations in France, while Finland’s Kutsuplus DRT service recorded an average cost of EUR45 per trip during its first year of operation in 2014 (POCACITO,n.d.). Such high costs, and comparatively low use in some contexts have led to doubts as to how widely the DRT model can be generalised (ITF 2021). Some experience suggests that maintaining service until it reaches “critical mass” may be a key success factor. For example, the Ponds service in suburban New South Wales, which provides weekday first and last mile connections with three local train stations and a service to the local shopping centre, managed to increase ridership significantly between June 2019 and February 2020 and lower the cost per ride from AUD15 to AUD7.40 (LEK, 2020).
These experiences point to the need for careful design and market testing. Integration with the rest of a public transport network is an important consideration that helps to ensure an attractive service that fills a gap in the market.
For specific services (e.g. airport transfers, hospital transport, links to out of town shopping etc.) commercial partnerships could be sought to subsidise costs.
For users, the cost per trip may be higher than conventional public transport, but experience indicates a willingness for both car users and existing bus users to pay a higher fare to use these services. Nonetheless, DRT should be part of a broader, multimodal package of solutions that supplements regular public transport services.
DRT has the potential to reduce waiting times compared to conventional public transport, thus providing improved service quality and attractiveness, and helping to increase public transport’s modal share. This can help underpin to wider behavioural change, as was seen with the UbiGo MaaS pilot in Sweden.
DRT can also increase access to social and economic opportunities, particularly for vulnerable users without access to private cars (e.g. elderly, people with disabilities, lower income families).
The extent of the carbon reductions achieved will be slightly limited by people substituting on-demand transport for travel by active modes (walking, cycling). Such substitution represented around 9% of trips in the Finnish case study cited above. This suggests the use of complementary policies designed to support active transport use.
Similarly, to maximize the level of substitution away from private car trips, policymakers should consider supporting policies that provide disincentives to car use.
Many countries do not have specific legislation addressing DRT. This can make it difficult to establish contracts and services, and add complexity to procurement and contracting processes. Explicitly addressing DRT in legislation and guidance material can help to simplifying these processes and facilitate the adoption of on-demand transport trials. A key consideration is the need to maximise the number of potential service providers. Tender and operator licensing requirements should be adapted to allow local taxi, DRT and community transport providers to bid for public service contracts in rural areas. (ITF, 2021a)
A lack of data on trips not taken due to a lack of transport availability can make it difficult to estimate the likely uptake of DRT. Adopting pilot programmes can provide a means of better assessing likely demand.
ITF (2021) Transport Climate Action Directory – On-demand public transport
https://www.itf-oecd.org/policy/demand-public-transport
ITF (2021a), Innovations for Better Rural Mobility, ITF Research Reports, OECD Publishing, Paris.
ITF (2021b), ITF Transport Outlook 2021, OECD Publishing, Paris.
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CERRE (2021), “Mobility as a Service (MaaS): A digital roadmap for public transport authorities”, report January 2021.
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Lynott, J. (2019a), Universal Mobility as a Service”, Presentation, AARP Public Policy Institute, https://onlinepubs.trb.org/onlinepubs/Conferences/2019/DRT/JanaLynott.pdf.
Lynott, J. (2019b), “FlexDanmark Optimizes Scandinavian Software Solution to Deliver Efficient, High Quality Transportation to Its Citizens”, AARP International: The Journal, Vol. (12), pp. 52-57, https://doi.org/10.26419/int.00036.015.
Nelson, J.D. and S. Wright (2021), “Flexible Transport Services”, in C. Mulley, J.D. Nelson and S. Ison (eds), Handbook of Public Transport, Routledge, Abingdon, Oxon, United Kingdom
Papanikolaou A., Socrates Basbas, George Mintsis, Christos Taxiltaris (2017) A methodological framework for assessing the success of Demand Responsive Transport (DRT) services, doi.org/10.1016/j.trpro.2017.05.095
Pettersson, F (2019), An international review of experiences from on-demand public transport services, K2 Working Paper 2019:5, https://www.k2centrum.se/sites/default/files/fields/field_uppladdad_rapport/on-demand_pt.pdf
POCACITO (n.d.), Smart City – Good Practice, Transport and mobility, On-demand bus service Kutsuplus, https://pocacito.eu/sites/default/files/Kutsuplus_Helsinki.pdf
Ryley T., Peter A. Stanley, Marcus P. Enoch, Alberto M. Zanni, Mohammed A. Quddus (2014) Investigating the contribution of Demand Responsive Transport to a sustainable local public transport system, doi.org/10.1016/j.retrec.2014.09.064
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