So, to recap parts one and two. If we make transport more efficient, less polluting, or generally more pleasant, then people just travel more and wipe out the benefits. We need to manage the overall demand for travel. We can do that by changing planning so that the things we need are closer to us, and by reallocating space and resources to the modes we prefer, like walking, cycling and buses.
But, and it’s a big but, even if we created perfect towns and cities, with everything nearby, we might still all travel just as much. That’s because we also have to think about the time people spend travelling, and the fact that humans are mostly creatures of habit.
Ever since Tanner suggested the idea in 1961, there’s been an ongoing academic debate about the idea of ‘travel time budgets’. In the 1970s empirical research by the likes of Szalai and Zahavi backed up the idea that all over the world, people spend roughly the same amount of time per day travelling – about an hour.
This caused quite a bit of excitement, suggesting as it did that maybe the amount of time we’re prepared to spend travelling is somehow ‘hard wired’ into human beings. Since that original paper various theories have been suggested, and plenty of other researchers have questioned the data, saying there’s more variation within and between populations than has been suggested.
What does seem to be agreed on however is that at the individual level, we do tend to be quite resistant to changing how much time we spend travelling. A look at the national travel survey for the UK (2010) shows that travel time has remained static for the last 15 years, at just over an hour per day, while the number and length of trips has varied. And if you think about it, that has some pretty far-reaching consequences for how we think about managing the overall demand for, and impact of, travel.
Suppose we drastically shorten many of our journeys, or provide really fast, efficient trains, or use the internet to eliminate journeys altogether? Well, the evidence suggests that on an individual level, we’ll probably just make other journeys to use the travel time we saved. The likelihood is that if we shorten ‘essential’ travel, to work, or that hospital appointment, it will be replaced with leisure trips, maybe occasional longer trips to see friends or relations.
Here’s another thought, transport economics is almost entirely based on the idea of time savings. The case for a new road will typically be based on the idea that, for example, (a) each motorist will save 30 seconds off their journey time, (b) the average person’s time is worth £12 per hour to the economy, and (c) 200 million journeys per year will be made on the road. So, each 30 seconds is worth 10p, and the road is therefore worth £20 million per year to the economy.
You might think this is nonsense, because when you boil it down to the individual motorist, that 30 seconds is unlikely to really make any significant difference at all to their productivity. And I would agree with you. However, that hasn’t stopped government using the same method to justify investing billions in high speed rail.
But that logic is weakened still further if you assume that for each person, travel time per day will probably remain constant.
The upshot of all this is that we need to sustainably ‘reallocate’ any travel time that we save by speeding up or eliminating trips. It’s just the same as the need to reallocate road space if we want to ‘lock in’ the benefit of some motorists switching to other modes.
What might this look like? Well, having freed up time, if people are going to make extra ‘discretionary’ trips to use that time, we need to make sure they don’t choose to make those trips by car. We can make it attractive to walk and cycle for pleasure, to visit friends and leisure facilities. We can invest in extra capacity on the railways, rather than speed – given that you can now work, watch a film or surf the net on a train journey, why do we need to spend billions making that journey slightly shorter and massively more expensive? And we can stop chasing our tails building new roads.
Ultimately, perhaps what we need is a ‘slow travel’ movement, a bit like the ‘slow food’ movement? A shift in the focus of transport strategy, away from speed, and towards making travel healthy, low impact, and fun.
[P.S. One thing not addressed here is the impact of ‘outsourcing’ our shopping trips to delivery vans, via internet shopping. I think that will have to be the topic of another post.]