Julie Anne Genter

Basin flyover won’t solve traffic woes

by Julie Anne Genter

Some influential people in Wellington (including the editorial board of the Dominion Post) seem to have an unshakeable faith that a four-lane road from Levin to the airport, including a motorway bridge at the Basin Reserve, will solve substantial traffic problems in Wellington and support economic growth.

This will attract development and people. Yeah right.


Late last week, Wellington City Council split on a vote to oppose the Basin flyover, after a report from officials recommended it as the best option. The council now has no formal position regarding the project, which is opposed by the majority of residents. The Dominion Post criticised the Council for not caving to the bullying tactics of the New Zealand Transport Agency and supporting the project.

They can be forgiven for believing the engineers at the New Zealand Transport Agency, Wellington City Council and the consultants supporting them.

Unfortunately, traffic engineers have never been economists, and the traditional engineering approach to dealing with peak flows of vehicles does not take into account the economic reality of price sensitivity of people.

Traffic engineers since the 1950’s have been approaching traffic like they did water – building bigger and bigger pipes to accommodate peak flows of vehicles.

The flaw in this approach is that people are not water. They make different choices about where to locate and how to travel based on price, availability and convenience. If we spend billions making it cheaper and easier to drive at peak, more people will drive. This undermines the initial benefits of time-savings, and results in higher overall costs of transport for the economy. It also undermines the investment in public transport, because it competes directly and makes it less commercially viable.

Motorways and roads with high traffic volumes also degrade the urban environment, significantly reducing adjacent property values. This causes more new development to go to far-flung green fields sites, which require people to travel by car, increasing overall traffic.

For some trips, the car will always be the best option. But once we have an established road network, the cost of expanding it to deal with peak flows a few hours a day has steeply diminishing returns – especially if each car is only carrying an average of 1.2 people.

Across the developed world, transport professionals have realised this, and are now investing heavily in solutions that maximise the productivity, that is the amount of goods and people moved, of transport infrastructure. Bus lanes, cycle lanes and heavy rail are all able to move many more people at lower cost. By making it easier for some to travel without a car, it frees up the roads for freight and those for whom the best option is driving.

But it takes a while for a new approach to filter into practice, especially in New Zealand.

The WCC report evaluating options at the Basin Reserve is inherently flawed because it is mired in the old approach. It evaluates the options in terms of vehicles, not people and goods. It also assumes huge, unrealistic growth in vehicle trips at any cost.

The benefits extolled by the report are a time saving of up to 1.1 minutes eastbound, and up to 7.5 minutes westbound, during the peak. The traditional approach to assessing transport projects adds up the minutes saved and concludes there will be a material benefit to the economy.

If this isn’t “voodoo economics, I don’t know what is. There has never been any empirical evidence to support this theory. Indeed, former chief scientist at the London Department of Transportation, David Metz, wrote a book and several important papers on this subject in 2008, called “The Myth of Time Travel Savings”.

NZTA published a research report last year that backs up the international findings: “There was a very distinct propensity of respondents to report both their estimated commute time and their ideal commute time in 5 minute intervals. This could indicate that very small units of travel time savings (eg several seconds, or a minute or two) may be relatively meaningless to them, and hence should not be valued.”

There has also been significant research published in the last few years showing the traffic and economic benefits of removing elevated freeways in urban areas, such as the Institute for Transport & Development Policy’s “The Life and Death of Urban Highways”.

The argument against the flyover is not anti-car or anti-road. The argument is this project will not solve peak traffic problems. The engineering evaluation of options doesn’t take into account how humans respond in the real world, nor does it consider the factors most meaningful for the economy – how to move the most people and goods at lowest overall cost.

Those who want better transport and economic outcomes for Wellington should be sceptical of the proposed flyover and other measures that treat the roads of the city like a traffic sewer. A people- and good-oriented approach will reduce transport costs and improve property values. That is a far more likely way to support Wellington’s economy than hoping a new road will save a few minutes for car journeys at peak.