Riley Sutton is one of the first people to have access to a metro line in Sydney. But it hasn't improved his commute time, so he's still getting the bus.

Key points: Commuters are turning to alternatives such as share car services to help cut journey time

Commuters are turning to alternatives such as share car services to help cut journey time Transport experts suggest that multi-use hubs may be the way forward

Transport experts suggest that multi-use hubs may be the way forward Government figures found urban congestion will cost Australia $40 billion annually

"For me and a lot of people in the northern part of Cherrybrook, it's quite hard for us to actually get down to the Metro in a timely manner, so that it would beat those old types of transport," Mr Sutton said.

"At least for me it's about the same time to take the 620X and I don't have to change, so I'll just catch this bus for now.

"It's frustrating because I know the Metro itself is really fast … it's just getting down there."

After the $8 billion Metro Northwest was opened in May, bus routes were cut so now his commute is actually about 20 minutes longer on an extended route across a wider area to compensate.

There is a commuter car park at Cherrybrook Station but it fills up early in the morning, according to locals.

New data suggests the uptake of shared transport in Australia's outer suburbs could be the solution to some of these transport gaps, helping to ease congestion and trigger a fall in government spending on car spaces and off-street parking.

"The way we are using transport is changing — the love affair with the car is coming to an end," said the CEO of urban advocacy group Open Cities, Lisa McLean.

"Councils and state government do need to rethink building large car parks."

The CEO of urban advocacy group Open Cities, Lisa McLean, says transport is changing. ( ABC news: Kathleen Calderwood )

GoGet CarShare locations and transportation planner Josh Brydges said he was surprised by GPS trip data from Holsworthy Station in Sydney's outer west, where two share cars were recently introduced.

"We found that about 60 per cent of all trips were actually coming from people who live well far away from Holsworthy itself," he said.

"That's implying to us that a significant number of people are willing to travel on the trainline to get down to the Liverpool area and then jump into a car because they know that once you're down there it's very difficult to get around."

Mr Brydges said this gap was an example of the "missing mile" — a gap which makes it hard for people to complete their whole trip via public transport.

"So as a result, they just pick a car up from their home or their office or wherever and drive the entire trip," he said.

Better options

GoGet's data underpins an industry discussion paper titled Remode, Reprice, Reshape, which argues that commuters who ride in share cars, bikes and scooters also use more public transport.

Recent Government figures found urban congestion would soon cost Australia $40 billion a year, as drivers encounter average speeds of 11 kilometres an hour in all major cities during peak hour.

The paper also cites the success of Keoride, a Government-funded service on Sydney's northern beaches, which provides about 18,000 short trips a month.

Keoride customers use an app to contact the driver of a share car which provides transport between homes and local bus stops.

Government survey data found 96 per cent of Keoride customers said it was a better option than driving and parking their personal car.

For regular customer Michala Rothpletz-Tatt, who has an intellectual disability, it means she doesn't have to wait at Narrabeen for up to an hour after she finishes work.

"[The drivers] are nice to me … it has nice music," she said.

"They pick me up from Narrabeen and take me to the shop."

Keoride driver James Robertson and passenger Michala Rothpletz-Tatt. ( ABC News: Kathleen Calderwood )

Her mother Karla said it had changed their lives.

"It means that she can be more independent, she can come home. I run my own business which means I can't run and pick her up all the time, so it just means that she has more flexibility," she said.

Transport consultant Michael Comninos said NSW would spend more than $350 million on commuter car parking over the next three years.

"I think we need to consider how we use this scarce resource that is land around a station," he said.

"The old model of having a thousand cars sitting there for 10 hours a day, it's not the best use of that land.

"There's other options: can you activate it, can you put retail in it, childcare centres, electric vehicle charging stations [or] co-working spaces."

Experts said technology and culture had also fuelled the growth of shared transport, as younger people use apps to order more affordable on-demand services.

"Governments need to start thinking about integrated mobility hubs, where people have got lots of options when they may arrive at these hubs to get on a train, to get on a bus, to get on a scooter or a bike," Ms McLean said.