Rethinking Transport Modelling
28 June 2019

Rethinking Transport Modelling

This article features in the June issue of Local Transport Today.

Cost and time: do these remain the fundamentals that define how we travel, and the trade-offs we make when we plan our journeys?

By Duncan Irons
For decades in transport modelling the notions of cost and time have been axiomatic truths underlying just about everything we do. And yet, all around us, the traditional way of doing things is changing fast and our transport models should adapt accordingly. Models have responded in all sorts of ways to reflect new realities, but surely it is time to revisit those fundamentals, the very roots of what we do, and make sure we are still building on sound foundations?

The classical transport model conceptualises a journey as a sort of dead space between two life points; home and work, perhaps, or work and leisure. Of course, the traveller can do lots of things to make a journey a more positive experience – reading, listening to music, eating and so on – but traditionally the premise has been that travel time is a loss and it makes sense that quicker is better. And, all things being equal, the average person will pay to achieve that. But the interconnectedness of the digital world is challenging that idea. Mobile computing and wifi mean that travel time can be highly productive, if the conditions are right, especially for the increasingly large number of laptop warriors who are relaxed about flexible working and used to carrying their office with them. For travellers like these, the speed and price of the journey may be less of a priority than whether they can be guaranteed a table seat on the train, good wifi and a plug socket.

Equally, for many travellers, especially among younger generations, environmental issues are beginning to shove aside other considerations when choosing a mode of transport. These eco-minded cohorts seem to have abandoned the car and will choose to incorporate walking and cycling into their journeys even if it costs them considerable time, not just because they want to minimise emissions, but because of the value they place on the pleasure and positive impacts of a healthier lifestyle. And this, in itself, is an important re-thinking of urban travel and commuting. The question these young people are asking is why should such a major part of life be treated as a pill that has to be swallowed instead of something valuable to experience? As cities adapt to improve cycling and walking infrastructure, they reinforce such choices by making them more practical and pleasurable and set a virtuous circle rolling that leads away from more conventional travel patterns.

The availability of mobile apps that process data to co-ordinate this growing ecosystem of transport modes and to help travellers plan and connect their journeys is adding ever more complexity to the patterns of behaviour that we can observe in the real world. This is a phenomenon that is unlikely to slow down. More and more data are becoming available and developers are quick to grab it and give users ever faster more responsive feedback and better planning tools. We can see a wide range of user types developing in response, from those who plan hardly at all, but rely on real-time live information to get them smoothly through their journey, to the heavy-duty planners highly attuned to the benefits and incentives offered by providers for those who get in early.

And we have to assume we are only at the beginning of this huge social change. We are used to talking about Millennials as the apogee of the digital native, but already social scientists are talking about the next generation along: generation Z. These are a new wave of consumers who have grown up in a digital world far more advanced and developed than any previous generation and whose assumptions about how digital tech fits into and shapes their lives and work is bound to be altogether different than anything that has gone before.

The trend for young adults to drive less than previous generations began over 25 years ago. Today, young adults in the UK (and other countries) are driving far less now than young adults did in the early 1990s. Driving licenses among young people peaked in 1992 with 48% of 17-20 year-olds holding a driving licence and, by 2014, this had fallen to 29%.

Of course, there are many reasons: evidence indicates that the changes lie largely outside transport. Changes in travel behaviour have been driven by changes in young people’s socioeconomic situations; increased higher education participation, the rise of lower paid, less secure jobs and a decline in disposable income to name a few.

That said, many young people have become accustomed to a lifestyle in which private car use is less central than it has been for previous generations and will likely remain so throughout their lives.

These days, convenience now plays a bigger part in travel behaviour choices for younger people, especially in large metropolitan areas where alternatives to driving are more readily available and where there are greater constraints on driving.

Are we confident that our current transport models can adequately take account of all these technical, social and demographic changes? I don’t think we have any room for complacency. Most models do not even fully account for the arrival of Uber or similar services which for many young urban travellers is as natural a mode of transport as getting a bus was for their grandparents, let alone the potential earthquake that is driverless cars which seem always to be coming around the next corner.

So, what is to be done? As things stand, for any possible journey A to B, we model travellers who are essentially the same imagined person but with different priorities of cost and time. Like all models, it’s a simplification and one that has proven to be reliable and effective. So far. But for the world we are entering, that is no longer going to be enough. We are going to have to evolve our models to reflect a much larger cast of users with a much more complex matrix of needs and priorities or we are going to find that half of reality is lost to us. We need to think not just about where our traveller needs to get, when and for what price, but to ask what stage of life they are at?

The younger generation is generally assumed to be more price sensitive than older travellers, for instance, yet also more environmentally aware, more fitness focused, and digitally engaged. But older generations are not static. As the population ages we see older users using online tools to plan more and placing convenience and ease of travel above cost and time in their priorities. It may be that our traditional model of a rational choice between time and price may be found in between: the mid-career, perhaps with young children, time-poor, pressed for cash person. But if we assume he or she represents everybody else in what is an ever more complex picture, we could be making a mistake that could have far-reaching consequences.

The advent of the railway, nearly 200 years ago and air travel 100 years ago were quickly recognised as worldchanging events, shortening what had until then been vast distances, allowing people to travel between locations at unimaginable speeds. But what wasn’t instantly obvious was that these modes would not just change how people moved around in the world, they would change the world itself. Cities would change in size and shape and the nature of work and family life would be altered forever. What is true of trains and planes is true of all major new technologies. Our hand is shaped by the tool it holds. We are now experiencing the effects of a social change every bit as significant as those first trains and planes. Our modelling has to change just as profoundly.

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