The Campaign for Better Transport (CBT) believes new technology offers the opportunity for private hire vehicles to offer shared transport.
Utilising these vehicles should be a "key principle" for the future development of rural transport strategies in certain areas, the lobby group said in a report.
This is part of the CBT's call for a "planned network" to replace the existing "patchwork of different forms and types of public transport".
The report stated: "There is no sense of network - services are run by different operators, with little or no coordination between them and a lack of integrated ticketing."
The study warned there has been a "spiral of decline" in rural public transport in recent years as pressures on local government finances lead to cuts in support for bus services.
Rural bus mileage fell by more than 6% between 2011-12 and 2016-17.
During this period, patronage on supported bus services in non-metropolitan areas of England fell by more than 30%, with Wales recording a 44% decrease.
CBT chief executive Darren Shirley said constrained budgets mean councils need to work closer on transport with schools, hospitals and communities.
"The answer won't always be subsiding a bus," he said.
"It might be making sure a school bus turns into a public bus after 9am and using online technology to help people find lift shares or taxi shares.
"Rural public transport is in crisis. Bus cuts and shrinking transport networks are making it harder and harder for people to get to work or school, to visit friends and family, or access shops and services, as well as putting extra pressure on our congested roads."
Mr Shirley said "things need to change" and urged the Government to "realise the importance of rural transport".
Martin Tett, the Local Government Association's transport spokesman, said councils are "willing to discuss any ideas for shared public transport to help ensure communities get the services they need".
He added local authorities want to protect bus services but have been forced to make cuts due to "significant funding pressures".