Melbourne is a city defined by its soundtrack of dinging trams and the bells of boom gates lowering for train level crossings.

Key points: About 100,000 Melbourne households are affected by "forced car ownership"

About 100,000 Melbourne households are affected by "forced car ownership" Residents in the outer suburbs are disadvantaged by a lack of public transport

Residents in the outer suburbs are disadvantaged by a lack of public transport Car expenses can reach about $600 per week, leading to financial stress for many families

But that chorus dulls the further you travel from the city centre.

The outer suburbs are the domain of cars.

Professor Graham Currie, an expert on transport policy from Monash University, said residents were left with few alternatives.

"There's no choice for them to have a car, there's very little public transport on the fringe," Professor Currie said.

Cars double-parked in driveways and blocking narrow residential streets are a common sight, especially now that Australians are isolating and working from home.

During normal times, these cars spend time parked in inner-city parking lots, filling freeways or doing school runs.

Owning a car is not a luxury for many people living on the suburban fringe — it is a necessity.

About 100,000 Melbourne households are considered to have forced car ownership which can cause immense financial stress. ( ABC News: Billy Draper )

In Pakenham, in Melbourne's south-east growth corridor, there are three adults living in the Ross household, which means three cars.

There's also a trailer squeezed into the driveway.

"You couldn't do it, you just couldn't manage to get everywhere we need to be without the cars we have," Carmel Ross said.

The family has a station wagon and a covered trailer which her husband, Collin, uses for his job, doing home and garden maintenance.

"I probably spend 30 hours a week driving, all up," Mr Ross said.

Mrs Ross uses their second car to get to work.

They both help to run their daughter Zhimei, 14, an hour up the road to where she does gymnastics training.

Their 20-year-old son Caleb's car was handed down from his older sister when she upgraded.

"We deliberately made our driveway bigger because I knew our teenagers were going to have cars one day," Mr Ross said.

'Transport poverty' in Melbourne's suburbs

Theirs is a very normal story in the outer suburbs, where housing is more affordable but people own more cars.

Professor Currie said Australian cities were unlike many others around the world because here low-income groups tend to live on urban fringes, where they can afford the great Australian dream — their own home on a block of land.

"They like the idea of living on fringes and having cars," he said.

"A lot of them don't realise how expensive running a car is and they buy houses in these areas and find they have a problem."

For low income earners, it is known as forced car ownership and it affects about 100,000 Melbourne households.

"Generally, if you have a household income less than $1,000 a week and you run two or more cars on the fringe, you're in it," Professor Currie said.

"About one in 16 houses are in this problem area of having what we call transport poverty.

"They've got good mobility but it's really putting pressure on their incomes and household expenditure."

Professor Graham Currie said a lack of public transport in the outer suburbs leaves families without many options. ( Supplied )

'Disadvantaged' without a car

In Dandenong, 35 kilometres south-east of the Melbourne CBD, 87 per cent of people drive to work.

That is compared to 62 per cent of the wider Victorian population.

In the inner-city area of Port Phillip, the number of people who commute by car fell to 56 per cent.

Financial counsellor Sue Deland works with communities in Melbourne's south-east and said public transport was a luxury some households do not have access to.

"Who wouldn't want to get on the tram, really?" she asked.

"[It's] nice and easy into the city, but you don't have that luxury here."

Ms Deland works at the Casey North Community Information Service and her clients come from one of the city's main growth corridors.

"You don't really have the luxury of guaranteeing that you're going to be working around your area," Ms Deland said.

"If they don't have a car they're disadvantaged."

Ms Deland said it could cost families in excess of $500 to $600 a week just for car expenses.

"If you're a family you need two cars, one to get around during the day, getting kids to school and then the other one, getting people to work," she said.

"It's a big stress and most people would be in deficit.

"They're just trying to balance their budgets as best they can."