We now know officially that Sydney rail commuters are feeling the squeeze with several of our busiest lines nearing capacity, and it is only going to get worse. Much worse. The news was revealed recently by Fairfax in response to a freedom of information inquiry, with the Bankstown and Illawarra lines reaching capacity by 2021, and the Western Line is struggling to cope right now. None of this would come as a surprise to weary commuters as they squeeze three to a seat if they’re lucky, or stand shoulder to sweaty shoulder as they fight for space in the aisles. At least they can comfort themselves with the thought that Prime Minister Tony Abbott has kept one election promise, one that he repeated often in advance of the 2013 election:

“Now the Commonwealth government has a long history of funding roads. We have no history of funding urban rail, and I think it’s important that we stick to our knitting and the Commonwealth’s knitting when it comes to funding infrastructure is roads.”

Why, oh why, oh why? If there were a single promise the residents of our major cities would have loved our “Infrastructure Prime Minister” to break, it was this one. But Abbott has indeed stuck to his knitting, every dear old 20th-century purl and plain road-building stitch of it.

This unfathomable position is not based on economics. Road congestion is at crisis levels in most of our capital cities and, if not addressed, will cost us $20 billion by 2020, according to figures from the government’s own Bureau of Infrastructure, Transport  and Regional Economics (BITRE). And it’s not just the loss in productivity at the workplace. Ask any commuter who spends three hours a day in the traffic what it means for productivity in the home. Goodbye to the evening read with the toddler, the chance of a coaching gig with the under-10s soccer team, or membership in a local social group, even though we know that it’s these little things that add up to a balanced, meaningful life.

Of course, we should maintain our existing roads and build new ones if the evidence shows there will be a decent economic and social return. But with one commuter train having the carrying capacity of a 10-lane highway, surely investing in better rail lines is more sensible than laying down ever more tarmac. And let’s not overlook the beauty of the bus. This nimble, adaptable and generally dependable form of transport, particularly the rapid-bus transit systems with their separated lanes, can be rolled out at a fraction of the cost of new heavy rail or even light rail. Since the installation of Brisbane’s South East Busway, travel times along the length of the route have dropped from one hour to just 18 minutes, a saving of 70%. Not surprisingly, patronage has jumped by 56% compared to the regular suburban bus line, with one-quarter of new patrons being former car commuters. Every extra person on a train or a bus means potentially one less car on the road, reducing the misery of road congestion for those who have no choice but to drive.

The economic merits of public transport in relation to health are particularly stark. Toss car, commuting and health into your search engine and you’ll see what I mean. A Victorian study of 43,800 people found that people who use public transport on any given day spend, on average, 41 minutes walking or cycling as part of their travel. For car users, it’s a paltry eight minutes.

It’s hardly news that Australian rail users are feeling the crush. Three years ago, the University of Sydney’s Institute of Transport and Logistics Studies discovered almost half of the nation’s train travellers found overcrowding at peak times made travel “intolerable”, with up to 40% forced to stand for between 60% and 100% of their journey. “Crowding … has become a greater concern for many rail and non-rail users than other factors such as travel time and fares,” wrote the institute’s director, Professor David Hensher. And two years ago, the federal government’s own BITRE figures noted that “urban public transport demand should increase by about one third between 2010 and 2030, with implications for infrastructure provision and other policy issues associated with public transport in our cities”. Transport academics have been writing about this for some time.

The Abbott government must take a mode-neutral approach to future funding decisions and open its eyes to what other successful world cities are doing. It must embrace a nationwide public transport improvement program based on economic merit as assessed by the arm’s-length arbiter, Infrastructure Australia. The Gold Coast’s G:link light rail system, the Regional Rail Link in Victoria and the visionary Perth City Link were three rail projects funded under the former Labor government in this way.

It would also be a wise — and a comparatively modest — investment in the health and productivity of the nation if the federal government were to partner with the states and councils on an extensive set of cycle and walking paths, connecting our schools, major rail stations and employment hubs such as hospitals and universities. Many people would be prepared to walk or hop on a bike — at least for shorter neighbourhood trips — but they won’t do it if they’re forced to dodge buses and trucks.

It’s not as if the rest of the world isn’t doing precisely this. New York City, at last count, had built 430 kilometres of new bike paths since 2007, a program begun by Republican mayor Michael Bloomberg.  Now 20,000 New Yorkers commute to work by bike each day, people who would otherwise be crowding the subway, or the roads in their cars. In Seville, 70,000 people now hop on a bike each day along 120 kilometres of new pathways. In Denmark, one-fifth of all daily trips are taken by bike and more than half of those are taken by women. Bike paths are comparatively cheap. You can buy 110 kilometres of cycleway for every kilometre of road. Safe cycle paths around our schools is not just an investment in our children’s health; they also free our roads from the scourge of the school drop-off, a significant contributor to the morning mayhem on our local streets.

Tony Abbott must abandon his crazy knitting thinking and step boldly into the 21st century. Yes, Prime Minister, please do break that election pledge, and a nation will turn its grateful eyes to you. Being the self-proclaimed Infrastructure Prime Minister has to be much more than simply ticking off the next big road project. More and more roads have never been the answer because urban traffic is like a gas that expands to fit the available space. Build it, they will come and they will very soon fill it. Think Harbour Tunnel. And just as Melbourne has done in abandoning the planned East West Link, it might be time to rethink Sydney’s own great big new road, the WestConnex. The best bang for all those billions, and a vote winner at that, could well be relieving the squeeze on the Bankstown line.

*Vivienne Skinner is principal of the urban strategy company Metropolis — Liveable Cities and was a senior adviser on urban matters to the former federal Labor government. She is a master’s student in urban policy and strategy.