More roads will only encourage more cars, more congestion and more emissions. Pat Baskett makes the case for ‘traffic evaporation’ – an idea successfully pulled off overseas but which would take a little getting used to here in NZ. 

COMMENT: Last Sunday a thousand cyclists stormed the northern lanes of the Auckland Harbour Bridge. The scenes of police trying to hold the barricade seemed alarmingly unreal. But cyclists are right to push for access to the bridge. It ought to be possible for those who want to commute by bike to and from the North Shore, to do so.

After all, the changes they have made in their lives are real contributions to reducing our CO2 emissions, 47 percent of which are produced, in one way or another, by transport.

One year ago climate scientists reported that by their calculations we have a mere decade in which to reduce emissions by amounts that will keep us within a 1.5 degree temperature rise by the end of the century.

The most visible sign of people’s failure to take this warning seriously must surely be the exponential increase in sales of SUVs and double cab utes. These vehicles emit approximately 20 percent more CO2 per kilometre than a modest sedan so it’s disheartening to see so many being driven to collect children from schools in the suburbs.

What the cyclists’ episode on the bridge points to is an alternative way of thinking about traffic. The group called Liberate the Lane were asking for a three-month trial period over the summer of one lane on the bridge dedicated to cycling. Waka Kotahi gave the expected thumbs down.

It’s common knowledge that building more roads brings more traffic – numerous studies show that 10 percent more roads will bring an equivalent increase in traffic. This is called “induced traffic”.

Less familiar is the term “traffic evaporation” which describes the effect of reducing the car-carrying capacity of roads. Its effects are a mirror image of building roads. The result is that people find other ways of travelling and traffic is reduced.

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A study of 100 locations in the UK of 1998 showed that after a “settling in period” where road capacity was reduced for private cars, there was an overall 25 percent reduction in traffic. The example of Copenhagen is well known – and took place more than 20 years ago. By cutting parking spaces, removing road lanes and banning certain through traffic in the 1990s, traffic was hugely reduced and congestion was no longer a problem.

The thousand cyclists on the harbour bridge were quite a sight. Maybe not all were familiar with the term traffic evaporation but most were there because they want to cycle further and more safely. Before engineering problems ruled out the clip-on bike lane Waka Kotahi, the NZ Transport Agency made plans for a Northern Pathway, a cycling route all the way from Westhaven to Albany. Cyclists would cross the bridge and leave the motorway at the first exit, Stafford Road.

The mere suggestion of closing a lane on the bridge gives motorists nightmares – but it would not do so if used in combination with a raft of traffic reduction strategies. Auckland is said to acquire 800 more cars every week – imported used and new. Five makes of diesel-powered SUVs are the most popular new purchases and anybody can drive anywhere in any vehicle, including outside schools.

This is a privilege we take for granted. But diesel vehicles have had restricted access to European cities for years and many cities have congestion charges according to the emissions of all cars. In London, where a congestion charge was introduced in 2003, the case was simple: to reduce traffic in the city and generate funds to reinvest in public transport.

The system is being continually extended and changes this year will mean that London will have three distinct road-charging schemes – a Congestion Charge, a Low Emission Zone and an Ultra Low Emission Zone. The latter zone will be extended from October 2021 to include large suburban areas between the North and South Circular Roads.

Paris has a graduated scale which will see all diesel vehicles banned from July 2024 and culminate in a total ban on all fossil-fuelled vehicles by 2030. Only electric or hydrogen fuel cell vehicles will be allowed inside the circular road that delineates the city centre.

Cyclists showed up in droves for the event. Photo: Facebook/Bike Auckland 

Sure, London and Paris are large conurbations of greater complexity than any of our cities. But Auckland is not far behind and congestion, on a par with population increase, is as bad as in any city.

Auckland City Council doesn’t need the authority of a government bill to act to restrict where we can drive. The system could accommodate residential parking areas in the inner suburbs of Ponsonby and Parnell. Vehicle numbers in the CBD would reduce as people either used buses or found alternative venues for their activities.

As a means of reducing our appalling transport emissions, limiting where cars can go and congestion charging are a pretty cheap fix. This would require a bold and efficient bureaucracy but no new infrastructure and would bring in revenue. As strategies per se this didn’t figure in the Climate Change Commission’s Draft Advice for Consultation, despite its clear message of the need to de-carbonise transport and that imports of fossil-fuelled cars will have to cease by 2030.

Electric vehicles will make a tiny dent in our emissions but do nothing for congestion. Will there be enough to go around? Will public transport meet the demand? We should be practising now for a different way of moving around. As individuals, most of us non-cyclists have changed nothing, or very little of significance, in our daily lives. Council action to limit where we drive would be a nudge that surely few would resent. Is the climate crisis an emergency or not?

Here’s a key comment from the International Energy Agency’s most recent report on climate change:

“Achieving net zero by 2050 cannot be achieved without the sustained support and participation from citizens. Behavioural changes, particularly in advanced economies – such as replacing car trips with walking, cycling or public transport, or foregoing a long-haul flight – provide around 4 percent of the cumulative emissions reductions in our pathway.”

Not much? But each of us has to do something. The latest Greenhouse Gas Inventory, released by the minister for the environment in April, shows that both gross and net emissions increased by 2 percent in the 12 months to the end of 2019.

Thanks, cyclists, for showing us one way.

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