And yet one looks at Google Maps shows the uncomfortable truth — that the multi-billion dollar road projects are those that now have the biggest jams.

Far from speeding up the commute, shiny new motorways are getting clogged up as people are encouraged to jump back in their cars.

“Building new road or public transport capacity doesn’t solve congestion,” a damning new report by think tank the Grattan Institute said today.

Indeed, the modest overall rise in traffic speeds which expensive new roads brought about could be achieved for little if any cost by simply charging minted motorists to enter the CBDs of Sydney and Melbourne.

“It’s pretty hard to get a 1 per cent network wide rise in speed,” the institute’s transport and cities program director Marian Terrill told news.com.au.

“You can get it by building a freeway for $16 billion, or you can get it through a CBD congestion charge with no cost to the taxpayer.”

It’s an idea that many politicians are almost viscerally opposed to with the New South Wales and Victorian governments saying it was not on the agenda and one minister remarking bluntly: “It’s not going to happen.”

The Grattan Institute singled out Sydney’s $17 billion West Connex motorway and Melbourne’s $16 billion North East Link freeway for scrutiny.

It’s estimated that the former, which is already part open, will increase travel speeds on Sydney’s overall road network by 1.7 to 3 per cent.

North East Link is projected to increase speeds by about 1 per cent across Melbourne.

Yet similar, or exactly the same, increases in speed could be achieved by simply charging drivers to enter the CBDs of each city in the peaks.

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Under a congestion charge, roads within the CBDs would see 40 per cent fewer cars, speeds would increase by up to 16 per cent and 20 per cent on arterial routes leading to the CBD. But in Sydney and Melbourne overall, even far from the CBDs, cars would go faster by 1 per cent.

MAPS REVEAL CHOKE POINTS

Just a look at Google Maps on a weekday afternoon shows some of the biggest, most expensive, roads are also the most congested.

Google’s live traffic tool shows that the Sydney Harbour Tunnel, opened to much fanfare in 1992, is typically jammed most weekday afternoons. As are the Eastern and Western Distributors.

The intersection of the Eastern Distributor and the Sydney Harbour Bridge is shown as one of Sydney’s most clogged roads. That will come as a surprise to absolutely no one who has spent many evenings after work snaking round the CBD to get across the harbour.

In Melbourne, the West Gate Freeway is choked with traffic and is the busiest single road in Australia with 200,000 vehicles a day.

FUNDAMENTAL PROBLEM WITH NEW ROADS

Newer roads, such as the recently opened WestConnex M4 East in Sydney, remain relatively clear now. But history suggests that won’t be the case for long with new roads tempting people back into their cars.

“Because drivers travelling in peak periods converge on the best and quickest arterial roads and freeways, these become so clogged that they are no longer any quicker than small streets and roads,” the report stated.

“If an arterial road or freeway is upgraded with a new lane, or a new road is built, the new space serves not just the existing travellers but also some new ones, who had previously timed their trip to avoid the worst of the peak period or had previously travelled by (public transport) instead.

“This is the fundamental reason building new road or public transport capacity doesn’t solve congestion: the system never stands still.”

‘LEAST PAINFUL’

Congestion charging has been touted as the least painful way to squeeze more capacity out of existing roads.

“(Congestion charging) would lead to a better allocation of road space to those who most need it; it isn’t excessively expensive to implement — in fact, it would contribute to government coffers; and in the longer term it would encourage households and employers to make more sensible decisions about where to locate,” Grattan said.

A look on Google Maps at Swedish capital Stockholm, which has had a congestion charge for years, shows fewer roads snarled up in the peak. London’s roads are busier, but it is also a far larger city.

The Grattan Institute said as people driving into CBDs are generally on the highest incomes, a city centre toll is fairer.

However, other road experts are less convinced. Professor David Hensher, of the University of Sydney’s Institute of transport and logistics studies, favoured charging drivers for every kilometre they travel on any road in the peak.

“The way it works is you halve the rego cost and introduce a 5 cent per kilometre charge in the peaks,” Prof Hensher told news.com.au last month on the sidelines of the SMH Population Summit.

That would encourage more motorists to drive outside the peak freeing up precious road space, he said. But many drivers could be quids in as they will pay less rego and if they avoided the charge.

“It’s true that people in the CBD have relatively higher incomes but the proportion who drive is relatively small; 80 per cent of commuters use public transport already so there’s not a great deal of market to attack,” Prof Hensher said.

Politicians have given both schemes the thumbs down.

Victorian Premier Daniel Andrews said his Government had “no plans and do not support a congestion tax”.

NSW Roads Minister Andrew Constance has previously said: “It’s not going to happen. You provide better public transport; you don’t need to introduce a congestion tax.”

But Ms Terrill said it made no sense to rule out a CBD charge while new roads, like WestConnex, slapped motorists with a toll.

“They are happy to charge for new roads in the form of tolls but roads don’t stay new for very long and we should care about how clogged they whether than if the roads are old or new,” she said.