Friday, December 5, 2008

The case against a tunnel

NO one likes sitting in traffic jams. But there is a lesson we are now beginning to learn: we can't build ourselves out of congestion.

So, however tempting it is to relieve the frustrations of motorists on the West Gate Bridge, the State Government should not build the Eddington road tunnel from the Eastern Freeway, under Parkville and out to the Western Ring Rd.

This tunnel is an engineering project in search of justification. It does not need to be part of any systematic plan to provide for transport needs across the whole city, and across different modes of transport.

Although Sir Rod himself backed the tunnel (a project put to him by VicRoads), the detailed analysis in his report can be interpreted to tell a different story.

Try to think of roads like drainage systems. Water flows from small pipes from households into large fat pipes, then to sea.

Unlike drainage systems, road systems discharge people and cars back into narrow channels - the local streets and roads that contain people's destinations.

But, like water, the traffic will back up when the large pipe enters the small pipe system. So freeway off-ramps always become congested.

The Eddington analysis shows clearly that drivers crossing the West Gate Bridge or those entering the city from the Eastern Freeway have many destinations throughout the inner and middle suburbs.

Most drivers do not want to travel right across the city east-west or the reverse.

So relieving congestion at the ends of these freeways merely transfers the traffic congestion to the streets of inner Melbourne - on both sides of the city.

It opens the way to even more freeways, spaghetti junctions and flyovers throughout inner Melbourne. That's devastating to the local environment of homes, schools and parks.

Sir Rod Eddington recognised this problem and that's why he recommended providing no off-ramps on a tunnel that would run under Parkville and Royal Park.

But the analysis then showed that the road tunnel could not be justified economically because too few motorists would use it for a through east-west trip.

The only economic justification for the tunnel is the increased productivity that comes from reduced time spent in travel.

But the tunnel would return only 45 cents in value of time saved for every dollar spent. That's not a responsible use of our taxes. Yet even that calculation was optimistic.

But what would you do if you could save a few minutes on the journey - get to work earlier or get out of bed later? Time will be saved, for a few people, for a while.

But soon people and businesses will adjust their locations further apart to take advantage of the time saving.

In the long run, time spent in travel stays much the same, but distances increase.

We must face the fact that travel time per person has not fallen in Melbourne over the last 30 years, despite successive governments having built more freeways and relieved more bottlenecks than any other Australian state capital.

Like city people all over the developed world, Melburnians are discovering that car travel is indeed expensive.

The oil price has come down, but they know that it will go back up just as soon as global growth kicks off again.

They are transferring to public transport, causing congestion on trains.

Their demands that governments provide high-quality public transport before they spend more money on unproductive and environmentally damaging roads make sense.

And billions spent on an east-west tunnel is money not spent on public transport.

Prof Nicholas Low is head of Melbourne University's transport research centre

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