24 February 2014

Peak Travel and Outdated Projections

I had the pleasure of speaking at the Eco.ch conference in Basel last Friday. The theme was "Nature & Mobility - Increasing Mobility with Reduced Traffic". I gave a version of my Bicycle Urbanism by Design talk.

One of the other speakers was particularly great to listen to. Adam Millard-Ball from the University of Santa Cruz spoke about Peak Traffic and the future of traffic demand.

Future patterns of travel demand have enormous implications for energy supply and the environment. How far will we travel in the future, and by what modes? Has travel in the industrialized world ceased to grow – "peak travel"? Are developing countries likely to follow the high-travel, high-emissions path of the United States, or will their travel patterns look more like Europe or Japan?

He highlighted how engineers and traffic modellers insist on using the same old same old techniques for predicting future travel demand patterns. Despite the fact that they are hopelessly wrong almost every time.

The slide, at top, really says it all. He uses two examples. One is projections from the Department for Transport in the UK (at left) and from Washington State. It's a very intuitive slide. Actual traffic growth on both graphs is in black. The wild coloured lines shooting for the stars are the projections. Millard-Ball said that this is a tendency around the world.

Reality is quite different from the computer models still employed by transport departments. Models that produce projections that influence politicians and impact the lives of millions. Models that are wrong and hopelessly out of date.

As I describe in this TED talk about Bicycle Culture by Design, traffic engineering is an outdated science in its current form. Although that current form is largely unchanged for decades, so it's not really current at all. It's prehistoric. Take the 85th Percentile folly that still controls speed limits in cities. It's standard stuff at universities. Bizarre.

Traffic engineering has too much influence on the lives of our citizens. Nobody has bothered to dig just a little deeper and realise that it's quite hopeless and that we need innovation and new thinking to reverse the damage it has caused.

1 comment:

Graeme Jones said...

Will the underused tunnels in Australia lead to a change? Second hand, I have heard there is class action including the companies that did the modelling.