We used to feed carrots to an old horse, Nessie, who lived under a willow tree on a vacant block of land nearby.

Although the suburb had been settled quite early — the train station was built in the 1880s and author Miles Franklin’s family moved to a home a few streets down in 1914 — there remained plenty of big backyards and local parks.

By the 1980s the laneway was paved but traffic was gentle enough that we could still ride our skateboards down the middle of it.

Big changes in state planning laws by the second half of that decade allowed quarter-acre backyards to be sold off to fit two homes on one block. In more recent times, duplexes and villas were added to tiny parcels of land. And the latest wave of change has seen a boom in apartment building.

Last week my mother was blocked in, unable to get her car out of that back lane. The week before she drove to Sutherland Library for a seniors’ art class and was unable to park, so circled the streets for 40 minutes and then returned home.

Sydney — home to one in five Australians — now houses 5 million people, and we’re told another 2.4 million will call it home within 30 years. The latest census data reveals how Sydney’s population densities — measured by suburb — have exploded.

Hurstville’s density has now hit 6825 people per sq km — more than Bangkok’s 6450. North Bondi, by way of comparison, is 9168.

Three of Sydney’s inner city suburbs have a higher density than New York City’s notorious Bronx district’s 13,231 — Pyrmont-Ultimo (15,650), Potts Point-Woolloomooloo (15,756) and Darlinghurst (14,239).

Other suburbs have seen their population densities rise by more than 100 per cent in the decade leading up to the last census.

At Homebush Bay-Silverwater in the Auburn Council area, the density went from 844 to 1739, a 106 per cent increase. Waterloo-Beaconsfield rose 102 per cent to 9864, Concord West-North Strathfield rose 100 per cent to 5117 and Arncliffe-Bardwell Valley rose 59 per cent to 4589.

At Campbelltown, a flash new plan for the city says medium density will be built to cope with an expected 500,000 more people in three decades, but the planners suggest the new buildings will “decouple car parking from new developments to encourage less basements”.

Social demographer Mark McCrindle says there’s been no let up in car ownership rates among Aussies, and moves during the 1980s and 1990s to car pool don’t appear to have worked.

“The car is often the only viable form of transport that can do multiple things — the children’s drop-off to school, which is a generally new phenomena, as well as getting people to casual and part-­­time work,” he says.

“Despite increasing costs, tolls and parking and upkeep, cars continue to be the mainstay for Australians.”

McCrindle says more than half of all households have at least two cars, compared with less than 1 in 10 households in 1966.

Across Sydney, 15 per cent of all households now have three cars; 20 years ago the figure was 9 per cent.

The latest census shows multi-car families have been the norm for a while now in many suburbs. In the Hills Shire, 71 per cent of households have two or more cars. Almost a third, or 27 per cent, own three.

Sydney’s southwest suburb of Horsley Park, with a footprint of 22 sq km, tells the story in a nutshell.

It only has 517 occupied dwellings — but 503 vehicles were registered on the last census. In fact, more households own four or more cars than own three.

In 1966, 40 per cent of Australian households had no car, but now overdevelopment and issues about parking are cropping up in electoral polling.

Confidential electorate polling by the federal government, obtained by The Saturday Telegraph, shows Sydney residents nominating “overdevelopment” (also known as OD) as one of their main hot-button issues, even though it is more of a state than a federal issue.

A political staffer, whose job description is to take the pulse of Sydneysiders by making 30 phone calls an hour, says: “Overwhelmingly people are talking about OD.

Namely the fact duplexes are constantly going up (and) people are not using their garages and parking on the streets.

“Garage spaces are not big enough for cars; they mostly use them for storage.

“As a result, streets are getting narrower and harder to drive down.

“Families now have three cars if they have their adult children living at home, who can’t afford their own homes.

“People are ringing our offices asking for the streets to be made one-way, because they can’t pass down streets without pulling over.”

Seven of the nation’s 10 most congested roads are in Sydney.

At Wynyard, rail officials in peak hour hold white flags on sticks to push back the commuters trying to crowd onto trains.

Trains are running at occupancy rates of 180 per cent at the morning peak, and train bosses are considering installing screen doors on Town Hall platforms to keep people safe.

One of Sydney’s newest schools, The Ponds High, is full, despite being less than three years old. Administrators are now looking at bringing in 50 demountables.

Beyond demountables, now “pop-up” schools are being built and new high schools are being housed in high-rise buildings with playgrounds on the roof.

At Marrickville, developers have been forced back to the drawing board after residents protested against a $1.3 billion proposal to build 35-storey units.

Inner West Mayor Darcy Byrnes says the plans were over the top, and that “Mirvac has confused Marrickville with Hong Kong”.

“We get the residential density but none of the community and transport structure that will make it work,” he says.

Peter Olive, a spokesman for the Sydenham to Bankstown Alliance, represents 10 local community groups fighting plans for a series of developments along the rail corridor, where 36,000 new dwellings are planned.

“There is a massive shortfall in services to cope with the extra thousands of people, not to mention the provision of medical services, schools, local roads — none of these things have been accounted for in the government’s overall proposal,” he says.

“In fact, in the revised proposals they are saying there’s potential to rezone Canterbury Racecourse and turn it into some sort of residential area.”

Olive points out that there is a lack of playing fields for children.

It’s a concern that has been raised in other suburbs, too, where the number of winter sports teams has had to be restricted due to a lack of grounds on which to play and train.

“If you have another 8000 people in the suburbs of Marrickville and Dulwich Hill, then there’s going to be a massive increase in the number of children playing sport. You need the grounds to do that,” he says.

Childcare centres and preschools ration places and hospitals are showing the strain. “We can’t just keep on finding excuses for this unrelenting pressure and expecting hospitals to cope,” AMA NSW president Professor Brad Frankum says.

“We continue to be at record or near record activity every quarter and it is having tangible effects on people who work at our hospitals.”

In 1951, 10 Sydney councils were so worried about urban sprawl they joined forces and issued a plan to have a “green belt” circle of parkland around the city, coupled with a careful design of new highways to bring “fresh air and unspoilt countryside within the reach of as many urban dwellers as possible”.

They also railed against jobs being concentrated in the CBD, saying Sydney’s “famous” traffic problem was caused by so many people trying to travel there for work.

Jobs, therefore, needed to be provided in the suburbs. But developers attacked the plan and it didn’t get off the ground.

Western Sydney University assistant vice chancellor Dr Andy Marks says creating more jobs outside of the CBD is crucial to improving the quality of life for locals — many of whom travel 2½ hours a day to work.

“Every day there are 200,000 people from Western Sydney on the road going to Sydney for work,” he says. “The state government has done a great job on building the roads — but we need the jobs.

“We are not seeing from government or business or others in the community solutions that address the big jobs gap between Western Sydney and Sydney.

“There’s just no quality jobs in Western Sydney of sufficient scale. We are not seeing the reciprocal levels of investment or policy around jobs creation.

“Without that, this is nothing more than a dormitory set of suburbs to feed inner Sydney.”

The state government argues it is busy catching up on years of neglect, with Premier Gladys Berejiklian pointing to an astronomical $111 billion infrastructure budget for transport, health and schools.

At the start of this week she announced another $450 million for stage two of Nepean Hospital, transforming it into a mega $1 billion hospital. All up, the state government is spending $4.9 billion on health infrastructure in Western Sydney.

The Premier concedes planning in the past was “fragmented and chaotic”.

“As we build for the future, we are taking new approaches that would never have been possible in the past,” she says.

The Premier also emphasises planning will need to focus on “how this infrastructure improves liveability”.

But her hands are tied by the federal government’s immigration program, which has resulted in 86 per cent of new migrants settling in major cities such as Sydney.

Opposition Leader Luke Foley has called for the states and the Commonwealth to work together to devise a five-year plan on immigration in order to better manage a growing population.

“The capacity of our large cities to cope is being severely tested — and the test is greatest in Sydney,” he says.