MindsinMotion were there: Transport knowledge and planning practice

Transport planning has become quite holistic: interdisciplinary and taking different stakeholders and citizens in consideration. Listening to all of the conference speakers, it appears that the current practice provides two major topics for discussion:

• How and why are models used – and how should they be used?
• What should they encompass? Especially: how detailed or general should they be?

Symbolic
Organiser Marco te Brömmelstroet, who'll soon be finishing his PhD, said transport planning models frequently remain unused, “mostly for 'soft reasons' like lack of transparity or communication value, not for their price. The conclusion could be to stop modelling and use our common sense, or to further improve modelling through standardisation,” he added. “Instead we should choose the middle ground and use models for what they can, as learning tools.”

Henrik Gudmundsson of the Technical University of Denmark discerned a range of other model uses: “as eye-openers, to provide arguments in discussions, or not at all. He stated: “Symbolic use, for instance by politicians, is okay as long as they do not violate results. At least it is one step further than ignoring them at all.”

Dutch urban planning professor Harry Timmermans pointed out that policy makers often present model makers with a list of requirements to the model. “That is asking too much of the model,” he said.

Integration
A most pressing issue in the realm of transport planning models is 'land use and transport integration' in so-called 'luti models'. Almost everyone at the conference pledged for them, but in daily practice they are rarely used.

Most speakers saw their own models as (part of) the solution to the problems that arise when trying to represent reality.

Timmermans talked about Albatross, a model based on logic – not maths – that integrates even the household level (female participation in the workforce for instance) and systematically incorporates context dependent constraints such as shopping hours. But is modelling not primarily meant to escape contexts?

In the audience was a representative of the province of Gelderland, who supplied much of the practical response. He mentioned the balance between 'top down modelling', which leads to models “as complex as necessary,” and the 'bottom up approach', which amounts to “integrating the whole world into your model,” as he put it.

He also mentioned the need for his alderman to understand why a certain approach is chosen and to be able to explain it to citizens. But Timmermans pointed out that alderman nor citizens need to know how the model works. “They don't know how a plumber or a physician works either.” What is important, is 'intuitive consistency'.

Australian urban planning professor and decision maker in one Carey Curtis, showed how easily a good luti model can enlighten the general public, though. When citizens could actually see on a map how public transport meant accessibility of their own city regions, they immediately got enthusiastic.

In the matter of detail versus simplification Timmermans stated that the complexity of situations and the amount of aspects to be taken into account require increasedly complex models. But later on he agreed with transport modelling mogul Michael Wegener, of German urban research company Wegener and Spiekermann, who argued that too much micro results in “academic exercises without any practical value.” (See also the highlight in our conference announcement.) Timmermans added: “A paper model of a spitfire on a scale of one-to-one is not a paper plane, but a spitfire.”

The question of what models should encompass has yet another side to it. Daniel Johnsson, who's with the Stockholm Centre for Transport Studies, mentioned that in order to choose between models, factors like casualties are translated into 'costs you're willing to pay'. Some people find that immoral.

In a short wrap-up of the presentations thus far, meta models were suggested as a solution to the simplification question. They take the output of complex models and combine them into generalisations.

More tar
Induced traffic was a topic everyone got carried away by. If you build more roads, that leads to more traffic instead of solving congestion problems.

The modellers and transport planners at the conference, however, didn't seem to know that the concept of induced traffic is not taken for a fact in the rest of the world. Politicians and the general public are still arguing amongst themselves whether this effect can be expected. The argument is often considered a leftish, green party doom scenario, while many Dutch liberals adamantly state that more tar will solve congestion.

Dark side
Painting false pictures appeared to be quite common in the realm of transport modelling.

“I'll take you all to the dark side of planning,” Petter Naess, architect and professor at the Norwegian University of Science and Technology, announced with a sense of drama. Not only can models be used to manipulate and give a false picture, they also facilitate forecasting errors, like expected growth of future traffic or increase in travel time if a desired road is not built, or expected traffic reduction if it is built. Naess illustrated his point with the case of the third Limfjord crossing in Aalborg, Denmark as an example of unreliable and biassed traffic model forecasting.

Stop nagging
Paul Pfaffenbichler, of the Technical University of Vienna, lightened up the audience with his explanation of system dynamics, using a married couple to illustrate his point. If she keeps nagging because he goes to the bar every evening, and he goes to the bar to not hear her nagging, the couple has a problem. Funny thing is, both see their own attitude as a solution to the problem, not as the problem. There is only one solution: if one of the two does what seems illogical (either stops nagging or stops going to the bar).

In an analogy to this, various people in the audience suggested that maybe congestion is the solution instead of the problem, for it reduces traffic.

But, please, if you decide to join that traffic jam for the greater good, be sure do so in a zero-emission car.