Over recent decades, few could doubt that load pressures upon Australia’s roads have grown.

As the national population has roughly doubled over the past half century, the number of kilometres being travelled on our roads has grown almost sixfold from around 30 billion in 1962 to around 170 billion today, according to data from the Bureau of Infrastructure, Transport and Regional Economics.

Going forward, with the population expected to rise from around 22.7 million in 2012 to around 41.5 million in 2061, it would appear that demand for automobiles will rise, and that much more road capacity will be required. This is especially the case in metropolitan areas, with the population of cities like Brisbane and Melbourne expected to double. Should we keep going like this, Infrastructure Australia warned in a report last year, the annual cost of congestion throughout the country could rise from an estimated $13.74 billion in 2011 to $53 billion by 2031.

While some see this as evidence of a long-term need to put more money into building new roads, however, others believe the focus should instead revolve around the adoption of emerging technologies in order to maximise the use of our existing road network.

In this regard, three critical areas stand out. Ride sharing services such as Uber and vehicle sharing services such as Zipcar could lead to a number of those living in cities or inner urban areas to use these services in place of owning their own vehicle, which could lead to reductions in vehicle ownership rates. Growing use of technology which allows people to work from home or perform certain tasks at remote locations, meanwhile, will reduce the number of trips required into central offices.

The really big gains, however, revolve around autonomous vehicles. Operating at machine speed rather than human speed, these will not only be able to avoid accidents but will be able to be packed closer together as they do not need to leave a following distance from the car in front. This allows for more intensive use of existing road space and thus expands the capacity of existing roads. In addition, by eliminating road accidents caused by human error, it is hoped that these vehicles will not only prevent injuries and save lives but also help keep peak hour traffic on major roadways flowing by reducing the incidences of minor ‘prangs’ which block entire lanes and bring traffic to a standstill.

According to Telstra chief scientist Hugh Bradlow, the combined effect of each of these technologies could indeed be sufficient to enable Australian cities to accommodate the entire anticipated increase in demand bought about by the expected rise in population within the capacity of our existing networks today. In a paper presented to the Low Carbon Transport on the Move conference in Sydney last May, Bradlow and Telstra graduate Arjun Jayachandra modelled four different scenarios regarding the likely impact of the aforementioned technologies upon road demand between now and 2050 based on what they considered to be a set of straightforward but realistic assumptions.

Under the first scenario, the researchers assumed there was no change in either demand patterns or the way in which we operate our roads. Should this happen, they estimated that road capacity would have to grow by 250 per cent between now and 2050 in order to meet the extra demand that a roughly 60 per cent increase in the population would necessitate over that time frame.

In subsequent scenarios, the anticipated effect of each of the three technologies was progressively factored in. By the time all had been added in, road capacity requirements in 2050 were virtually no more than they are today despite the expected growth in population.

Bradlow says the potential of technology cannot be understated.

“It really does appear to be the case that digital infrastructure could substitute for physical infrastructure in the future,” he said.

Still, not all are convinced that the effect is going to be quite that big. Terry Rawnsley, a principal at SGS Economics and Planning and a renowned media commentator on the functioning of cities and regions, says that while the number of roads we will need to build going forward will fall, we will still be building new roads.

Rawnsley says traffic planners have had some success in persuading motorists who may not need to be on the roads during peak hour to instead use public transport or travel where possible during non-peak times – for instance by performing some work at home prior to going into the office. Satellite navigation systems which help direct motorists to use the fastest route along with cameras and electronic signs directing people into lanes and adjusting speeds have helped deal with peak periods to some extent, he says.

Still, he says many people continue to travel during peak hour. This, combined with expected growth in population, will mean new roads will still have to be built.

“The technology comes in at the margins but as Sydney and Melbourne grow from four to five million people to seven or eight million people, they will need some new roads,” Rawnsley said.

Nevertheless, Rawnsley notes that technology will impact traffic planning strategies.

In terms of new roads, the effect will be felt both in the number and type of roads being built. In Melbourne for example, while the past 30 years have seen the building of the Eastern Freeway, Eastlink, CityLink, lots of extensions to the West Gate, and extensions to the north on the Hume, the next 30 years will probably see only two or three big roads built. In terms of the type of roads built, he says these will largely be focused around new growth areas and ‘ring road’ types of roads which link growth areas to existing road networks.

Moreover, he believes the focus will shift away from new road construction to a degree and toward trying to ‘sweat’ existing assets by using technologies like the bunching up effect of autonomous vehicles to get more out of the existing road network.

Beyond physical road building and maintenance, Rawnsley says technology is also opening up the potential for market-based signals regarding who should travel on which roads and when. Rather than having everyone pay the same annual fee for registration, satellite navigation systems can be used to charge motorists differing amounts based upon the time (e.g. peak/non-peak) and distance they travel and how much congestion they contribute to. He says Singapore is already doing this and a number of cities in Europe are now taking this approach.

Moreover, in addition to ride-sharing technology, he says social factors will help to reduce vehicle ownership rates.

“Even 25 years ago, you needed a car to get around the city,” Rawnsley said. “If you didn’t have a car, you were disadvantaged in a lot of ways.

“Now, there are more people living in the inner city who will either catch a tram to work or ride their bike. They are the people whose cars probably sat in the garage not getting used apart from when the RACV came out and put new batteries in for them. These are the people saying ‘well, I don’t need a car – I can go to the station or I can use Uber. For those trips when I do need to use a car, I can use someone else’s rather than buy a car and spend a thousand bucks on insurance and rego for a year.’

He noted that this change means, and will continue to mean, fewer cars per person, adding that it will change the way people use the road network.