Understanding changing travel trends

At a national level we charging ahead with a few hand picked mega roading projects that will tie up our transport spending for the next decade or so. Unfortunately it doesn’t get much better locally with billions upon billions of dollars of ratepayer and taxpayer money proposed to go into transport projects over the coming decades, pretty much all of them relying upon significant traffic growth to be justified.

We’ve discussed changing travel trends on this blog for quite some time now, in particular the plateauing of traffic growth for an extended period of time since roughly the middle of last decade. Here’s a nice graph that Stu put together looking at vehicle kilometres travelled and car ownership rates over the past decade:

Similar trends are starting to show through in a whole variety of countries around the world. With billions of dollars being poured into roads in the coming year the real questions relating to this trend is understanding why it’s happening and then figuring out whether it’s a short term anomaly or the start of a much longer pattern of stagnant or falling traffic.

While New Zealand specific research into understanding the causes of these trends is strangely absent (Stu’s superb analysis aside), an increasing amount of analysis is being undertaken in the USA to ‘get to grips’ with what’s going on. And while shorter term issues – like the economic situation of the past few years – seem to undoubtedly have had some impact on the trends, it seems that there are some more major underlying cultural shifts which are perhaps making the biggest contribution. The New York Times picked up on this recently:

For six decades, Americans have tended to drive more every year. But in the middle of the last decade, the number of miles driven — both over all and per capita — began to drop, notes a report to be published on Tuesday by U.S. Pirg, a nonprofit advocacy organization.

People tend to drive less during recessions, since fewer people are working (and commuting), and most are looking for ways to save money. But Phineas Baxandall, an author of the report and senior analyst for U.S. Pirg, said the changes preceded the recent recession and appeared to be part of a structural shift that is largely rooted in changing demographics, especially the rise of so-called millennials — today’s teenagers and twentysomethings. “Millennials aren’t driving cars,” he said.

In fact, younger people are less likely to drive — or even to have driver’s licenses — than past generations for whom driving was a birthright and the open road a symbol of freedom. Research by Michael Sivak of the Transportation Research Institute at the University of Michigan found that young people are getting driver’s licenses in smaller numbers than previous generations.

Online life might have something to do with the change, he suggested. “A higher proportion of Internet users was associated with a lower licensure rate,” he wrote in a recent study. “This finding is consistent with the hypothesis that access to virtual contact reduces the need for actual contact among young people.”

Of course this isn’t a particularly ground-breaking observation – various studies and articles have been talking about younger generations not being as keen on driving as previous generations were at the same age. What’s particularly interesting is that this report has taken the recent trends and then applied them to forward travel projections under a number of “what if” scenarios to get an idea about what might happen in the future:

Young people aged 16 to 34 drove 23 percent fewer miles on average in 2009 than they did in 2001—a greater decline in driving than any other age group. The severe economic recession was likely responsible for some of the decline, but not all.

Millennials are more likely to want to live in urban and walkable neighborhoods and are more open to non-driving forms of transportation than older Americans. They are also the first generation to fully embrace mobile Internet-connected technologies, which are rapidly spawning new transportation options and shifting the way young Americans relate to one another, creating new avenues for living connected, vibrant lives that are less reliant on driving.

If the Millennial-led decline in per-capita driving continues for another dozen years, even at half the annual rate of the 2001-2009 period total vehicle travel in the United States could remain well below its 2007 peak through at least 2040—despite a 21 percent increase in population. If Millennials retain their current propensity to drive less as they age and future generations follow (Enduring Shift), driving could increase by only 7 percent by 2040. If, unexpectedly, Millennials were to revert to the driving patterns of previous generations (Back to the Future), total driving could grow by as much as 24 percent by 2040.

All three of these scenarios yield far less driving than if the Driving Boom had continued past 2004. Driving declines more dramatic than any of these scenarios would result if future per-capita driving were to fall at a rate near that of recent years or if annual per-capita reductions continue through 2040.

The different scenarios are then graphed:The real kicker point is when you start comparing these scenarios with past traffic volume forecasts – as shown below: From what we’ve seen previously, it appears that pretty much all future transport modelling in Auckland is calibrated to a 2006 base year – pretty much exactly when we started to see transport trends change dramatically. Presumably that will be updated when results from this year’s census come through, but if projections do end up being updated to reflect not only changing travel trends going forward but also the fact that what’s happened in the past seven years is rather different to what was likely to have been expected back in 2006, we could be in for some huge shocks.

In short, it wouldn’t be surprising for the justification for new roads becoming significantly more difficult. Which makes a lot of sense if the demand for them isn’t going up anymore. This issue was also raised by Green transport spokesperson Julie Anne Genter yesterday on Radio NZ.

Or listen here

Interestingly the NZTA responded to this.

Or listen here

Ernst’s claim that every road works for public transport and for active modes is almost comical. Just looking at Auckland, how many buses are using the Victoria Park tunnel, how many will use Waterview and why is there no cycleway planned for Puhoi to Wellsford and where is the promised walkway under the Newmarket Viaduct?

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