Transport Modelling: Learning from other disciplines

How can we as transport modellers take what is good in the profession?

Transport modelling has always attracted professionals from a broad church. I have worked with many a civil engineer, in fact I am one myself, and over the years my colleagues, students and mentors have included geographers, mathematicians, physicists and social scientists. I even once worked with a biologist –who coincidentally had completed a PhD on the subject of snails…

You won't be surprised to hear me say that transport modelling is not easy. The large geographical areas that our models cover; the intricate short term dynamics and interactions between vehicles, traffic control and transport infrastructure, the maddeningly complex and often irrational behaviour of travellers, our increasing desire as a profession to make models more complex mathematically but also quicker to compute, the constantly changing environment that our analytical tools need to reflect, the influence of weather and random events; it all adds up to one of the trickiest and most fascinating modelling areas I could imagine. An American colleague quoted to me last year: ‘Transport modelling, it is not rocket science. It is much more difficult than that!’

He was referring tongue-in-cheek to the Los Alamos National Laboratory – the birthplace of the atom bomb. In the late 1990s scientists there threw their weight, brains and super-computing power at understanding and simulating traffic flow. More than a decade later, all I have seen from this effort are a few research papers.

I'll stick my neck out: we are generally clever people with clever tools. We have lots to offer other disciplines. We can also be insular and a bit arrogant. Without a Masters degree, grey hairs and an intimate knowledge of WebTAG, surely you cannot be taken seriously? The modelling profession seems to forget that much of the progress that we have achieved over the years has been through learning from other disciplines, exploiting analogies (fluid mechanics, communication networks, market research), benefiting from breakthroughs elsewhere. What is now known as the Frank-Wolfe algorithm, was originally presented by its authors in a naval journal, long before transport modelling was commonplace, and only discovered by the profession in the 1970s. Similar stories can be told about the application and development of discrete choice theory, now such an integral part of demand forecasting.

2 years ago, the Transport Modelling Forum was renamed Modelling World. Doing this reflected three intentions:

• broadening the offering from just modelling to include data and visualisation. And last year, for the first time, the conference offered three parallel streams, and quite successfully;

• bringing in speakers, exhibitors and attendees from other disciplines, seeking to introduce new ideas. Remember the plenary about risk analysis?;

• exploring other areas where the skills and techniques developed in transport modelling may also be of use.
  

The opportunities for transport modellers applying their skills elsewhere are obvious. Some of my brightest transport modelling colleagues are already providing more general modelling and quantitative analysis services in Mott MacDonald, and to a whole range of non-transport clients, including in health, housing and tourism. My team has become a focal point for good practice in complex VBA programming in EXCEL, and for advanced GIS applications.  This is my point: perhaps it is time to shed the modelling prefix, and be proud to be modellers full stop. With the change in title could come a freedom to explore other areas of similar complexity, and with similar characteristics: long and short term dynamics, wide geographic coverage, socio-economic segmentation and response behaviour, and a new opportunity to discover different, better ways of representing the complexities of transport systems, than the software driven reality of the past two decades.

Inevitably, new and different transport model approaches would contravene the guidance in WebTAG. Is that really such a big problem?  In a recent on-line discussion one of the other participants complained that transport modellers have fallen victim to Group Think, whipping ourselves into a frenzy of protecting the status-quo. I have never believed that WebTAG should be used as a brake on innovation.  Of course, for major infrastructure investments a common methodology, common assumptions, common and minimum standards make eminent sense. But there are so many other applications of transport models where such rigour may be misplaced, limiting realism where existing tools are just not suitable, or making analytical support unaffordable.  Forcing UK best practice (as encapsulated in WebTAG) on projects anywhere in the world, where data, skills or future growth are so much more uncertain, makes little sense.  I may be abusing the term, but the concept of frugal innovation, developing tools and techniques where none existed, and at minimal costs, is relevant and exciting.

Which takes me back to this year’s Modelling World. With its roots still firmly planted in transport modelling, the event offers, even more so than last year, insights from other disciplines, exhibitors with products that you have not seen before, speakers that have new and exciting points to make.  I know that for years I have looked in vain for that breakthrough in speed improvements, for affordable visualisation and a better way in which to understand and represent real travel behaviour, and particular change in behaviour (what so many policies now seek to achieve).  I will scour the programme and exhibition for names, faces, concepts and products that I have not come across before, intending to learn something quite radical to use in my work during 2012. I hope you will join me.