It was once known as the 20-minute city, but Adelaide is now having growing pains, as suburban sprawl and road bottlenecks cause increasing headaches on the morning commute.

Key points: Modelling shows congestion will continue to worsen in Adelaide

Modelling shows congestion will continue to worsen in Adelaide There are hopes upgrades to the north-south corridor will improve flows

There are hopes upgrades to the north-south corridor will improve flows An expert says more needs to be done to encourage Adelaide residents to use public transport

It is Mark Shotton's job, with his team at the Traffic Management Centre, to handle the increasingly complicated road network and keep cars moving.

"Every year we get more and more cars on the road … we're more around the 25-to-30-minute city now," Mr Shotton said.

With the help of about 1,000 cameras, staff work around the clock clearing hazards, responding to incidents, and intervening to change traffic lights and speed limits where needed.

The city's north-south corridor suffers the worst congestion.

Traffic Management Centre director Mark Shotton hopes the north-south corridor will reduce traffic problems. (ABC News: Lincoln Rothall)

Infrastructure Australia modelling found that, in 2016, drivers on Fullarton Road and Goodwood Road spent 60 per cent of their morning commute in congested traffic.

And things are only set to get worse.

The modelling shows that almost everyone living between Glenelg and Port Adelaide currently live within a 30-minute drive of most jobs in Adelaide.

By 2031, to have the same commute, you would need to live in a much smaller zone.

Mr Shotton said new motorways under construction would eventually help some of that traffic move.

"Once the north-south corridor is completed, it's going to change the face of Adelaide," Mr Shotton said.

"I know it's a lot of pain during its construction, but as each section opens up, we get to move traffic further and further."

The area of Adelaide where more than half of jobs are within a 30-minute drive, according to modelling by Infrastructure Australia. (ABC News)

North-south corridor a 'dog's dinner'

That pain is acutely felt by commuter Donna Batchelor.

Her route to work involves rat-running down side streets to bypass bottlenecks, including roadworks on South Road.

Work to improve Adelaide's road network frustrates motorists stuck in traffic. (ABC News)

"It's a dog's dinner — I don't know how else to say it," she said.

"I can see the end result, but it's taken far too long to get there … and it has fundamentally made the trip into the city a million times worse."

On a bad day, Ms Batchelor spends three hours in her car commuting between the Adelaide CBD and her semi-rural home in Kangarilla on the city's southern fringe.

"I am stiff and sore by the time I get out of the car, and I feel tired by the time I get home," she said.

"It's just such dead, wasted time when you have to sit in traffic."

With its cheaper homes and bigger blocks, many people are moving to the fringes of suburban Adelaide, but transport options are limited.

She said using public transport would only lengthen her commute.

Car is king in Adelaide

The 2016 Census found that more than 85 per cent of greater Adelaide residents commuted to work in a private vehicle.

The city's residents are on par with Hobart as the most likely to travel by car.

Only 10 per cent of Adelaideans included public transport in their commute.

Transport engineering professor Graham Currie encourages more public transport investment. (ABC News)

In Sydney more than 26 per cent do.

Monash University's transport engineering professor Graham Currie said Adelaide should look to Europe for inspiration, where walking, cycling and public transport were much more attractive options for commuters.

It is a strategy attracting increasing investment in Melbourne and Sydney, where both state governments are spending more than $11 billion to construct major metro rail projects.

Sydney is also about to open a new $2.9 billion light rail through its CBD.

"We need higher-frequency services… [Adelaide] has wonderful services like the O-Bahn and the tram, but its coverage is very limited," Professor Currie said.

"We need more services like that to really encourage development of inner suburbs.

"Adelaide has an enormous CBD because of its great forward-thinking planning, and it's got a long way to go before it is fully built out."

Roadworks on the Darlington Upgrade are now due to be finished in mid-2020. (Supplied: DPTI)

Isolation leads to 'very poor' quality of life

Professor Currie said a "car culture" had led many Australian cities to develop in a low-density sprawl.

"It's been very successful for the growth of those cities … but that success has finished as we become big," Professor Currie said.

There is still room for development in Adelaide's CBD. (ABC News)

"Unfortunately, Adelaide is facing that stress now, a stress that most of the other big cities in Australia faced a few years ago and have turned around to a future which is moving away from the car."

He said another side effect of urban sprawl was that it forced people without cars, such as the young and elderly, to rely on others to get around.

"Younger people in the outer suburbs of Adelaide have less education participation, less employment work opportunities. And this is because transport dominates all forms of access," he said.

"The danger is isolation, and this is already an issue in southern suburbs and northern suburbs of Adelaide.

"We have studied these people, and we find that increasingly they have lower psychological wellbeing … their quality of life is very poor."

This is part five of South Australia's Our Changing State series that looks at how SA is changing and the challenges it must overcome.