Ditching fixed suburban bus routes would cut running costs in half in the ACT if on-demand public transport services ran instead, new research shows.
On-demand buses would also offer better services for passengers on routes with low demand, shaving between 15 and 36 per cent off travel times.
But the system, which allows passengers to request rides rather than relying on a regular timetable, becomes less efficient and more expensive when demand grows.
Replacing timetabled bus routes with an on-demand service that picks up passengers in a fleet of 12-seater vans and transports them within the district or to fixed, main routes would need more vehicles but save on fuel and running costs.
The current fixed network costs about $50 a passenger to run between 6am and noon, $40 a passenger between noon and 6pm, and sharply rises to $105 a passenger between 6pm and midnight.
The on-demand system, researchers said, could operate at a cost of $5 a passenger in the mornings, $10 in the afternoons and $24 in the evenings.
"The simulation results demonstrate that while PT operational cost remains steady regardless of demand change, there is a remarkable 85 percent reduction in operational cost during off-peak hours as compared to its peak operational cost," the research said.
Fuel consumption would also be significantly lower in times of low demand if the ACT switched to the on-demand system.
"There is a significant 90 percent reduction in [on-demand transport's] fuel consumption during off-peak hours as compared to its fuel consumption during peak hours," the researchers said.
"These findings highlight the flexibility and efficiency of [on-demand transport] in dynamically responding to varying demands and optimising operational costs and fuel consumption throughout the day."
Researchers from UNSW Canberra - Amir Mortazavi, Milad Ghasri and Tapabrata Ray - simulated the on-demand transport system in Belconnen, which has a population of more than 100,000 people and covers a 77 square kilometre area.
The system would need between 11 and 32 vans to transport the same number of passengers the existing network serves with 11 buses.
"However, [integrated demand responsive transport] can still be efficient, leading to reductions of up to 45 per cent travel distance (equivalent to 2400 km), 50 per cent operational costs (equivalent to $6360 AU), and 80 per cent environmental impact (equivalent to 1000 litres of fuel)," the researchers' paper said.
The study used real-world data from Transport Canberra's MyWay ticketing system to simulate where passengers would request to travel within the district.
On-demand buses could reduce overall travel distance by 46 per cent if the system was designed to minimise environmental impact.
But if the system is designed to minimise passengers' travel time, it would travel an extra 2000 kilometres compared to the existing system, a 38 per cent increase.
Cost savings of 61.1 per cent could be achieved in a system designed to reduce costs, but if the focus shifts to reducing passenger travel time on-demand buses would cost 2 per cent more than the existing system.
The researchers noted that even when the on-demand system is not focused on minimising travel time, average passenger journeys would still fall from 12.2 minutes on the existing fixed network to 10.3 minutes.
"In addition to the passengers' travel time reduction, [integrated demand-responsive transport] offers a more equitable distribution of delay among passengers," the researchers' paper said.
The paper, published in the peer-reviewed Transport Research journal, noted the actual travel time for passengers using existing bus services was on average twice the direct travel time.
The paper said future studies should consider the impact on-demand services would have on passenger demand, along with other potential impacts across the fixed-timetable network.
"There is potential for future research to delve into how the replacement of [public transport] with [integrated demand responsive transport] could potentially influence passengers' travel patterns," the paper said.
"This might encompass aspects like demand change, changes in passengers' origins and destinations, or alterations in passengers' travel times."
Canberra has experimented with on-demand public transport services in the past.
The Australian Capital Territory Internal Omnibus Network, known as ACTION, operated "Flexibus" services in 2005 which replaced fixed evening services.
Hailed at the time as an Australian first, the service allowed passengers to call ACTION's information line to book a pick up in a bus either from their house or nearest bus stop after 7pm.
But the trial was halted in 2006 due to "customer feedback that indicated a preference for scheduled rather than flexible routes", the government told the Legislative Assembly in 2012.
ACT Treasury in 2016 said a two-month trial of on-demand public transport services in Weston Creek and Tuggeranong would cost $500,000.
The service, a Greens election commitment, would have allowed passengers to be picked up or dropped off in the suburbs by taxi, linking with bus interchanges. The service was never trialled.
Transport Canberra now operates a flexible bus service for people with a disability and the elderly to access hospitals, shops, hospitals and medical centres.
Bookings need to be made two business days before travel and the services operate between 8am and 4.30pm, Monday to Friday.
