Wednesday, August 17, 2005
Tunnels? No thanks
A guest writer has been granted room in Brisbane’s The Courier Mail to editorialise against Lord Mayor Campbell Newman’s plans for a North-South Bypass Tunnel (“Fouling our nest”)

This is an interesting move by the paper, normally noted for its demand for ever more infrastructure to cure Brisbane’s growing pains.

The opinion writer – a post-grad student of Urban and Regional Planning at the Queensland University of Technology – takes the long view and argues that in 20 years time we may have regretted spending $1.4bn on building a tunnel for motor vehicles when we could have spent it on something else: public transport, for example.

Local air pollution is his main concern. Cars will spill thousands of tonnes of particulates and toxic chemicals into Brisbane’s air, with serious consequences for human and ecological health in the long term.

But he also alludes to the concept of induced demand: “[Politicians] argue that air pollution is caused by traffic congestion (not car dependence), and that building new or wider roads will fix these problems. “

This is true, as cars run most efficiently (if they run ‘efficiently’ at all) at some 70-80km/h. Improvements to the existing road system – particularly coordinating traffic lights or replacing them altogether with roundabouts – would appear to be money well spent. Building more roads would fix a problem from an intuitive engineering perspective.

But it is generally accepted now that increasing supply will simply increase demand “as additional road space is quickly consumed by people undertaking more and/or longer car trips in response to shorter travel times.” This has been demonstrated with quite obvious regularity in the persistently fruitless widening of the M25 London Orbital.

Congestion is a traffic demand management tool. It is blunt, counter-intuitive and not one that people particularly like, but it does work. Indeed, it should be made to work with even greater force by further reducing road space available to single occupant vehicles and ensuring that mass transit systems have priority over people who choose to bring a tonne of steel, taking up 10m2 of road space, to work with them every morning.

I seem to manage to fit everything I need into a briefcase weighing less than half a kilo.

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