There’s a long running debate over whether the flattening/decline of traffic growth over the past few years is attributable mainly to the rather ‘up and down’ economic situation over a fairly similar time period – or whether this reflects a more fundamental change in travel habits.
This is a critical question – on the one hand if the recent trends are due to the economic situation (certainly the position taken by NZIER economist John Stephenson at the transport conference I went to a few weeks back) then they’re just something of an anomaly and likely to ‘correct’ over time back to normal steady traffic growth. Under this scenario, the long term transport models we have that predict significant traffic growth in the future might be right and there may be some long term justification for many of the motorway we’re either building or planning at the moment (even if we’re perhaps building them too early compared to other transport priorities).
On the other hand, if the flattening or decline of traffic volumes is more independent of the economic situation then it may be a sign of longer term changes to travel habits. These longer term shifts potentially arise from changes such as a fundamental increase in the price of petrol, technological advances which mean that cars aren’t needed to interact with friends in the way they once were, urban structure changes which reflect a ‘re-urbanisation’, improved public transport and so on. The key point here is that these changes are likely to be fairly long-lived – fundamentally impacting upon future predicted travel growth, completely debunking transport models and having an absolutely massive impact on future transport needs.
A new study from the US PIRG institute looks at this question in a bit more detail – to try and understand in more detail the changing travel patterns across the USA over the past few years. Some key headline findings outline in the report include:
- The proportion of workers commuting by private vehicle—either alone or in a carpool—declined in 99 out of 100 of America’s most populous urbanized areas between 2000 and the 2007-2011 period averaged in U.S. Census data. (New Orleans was the only exception here).
- From 2006 to 2011, the average number of miles driven per resident fell in almost three-quarters of America’s largest urbanized areas for which up-to-date and accurate Federal Highway Administration data are available (54 out of 74 urban areas).
- The proportion of households without cars increased in 84 out of the 100 largest urbanized areas from 2006 to 2011. The proportion of households with two cars or more cars decreased in 86 out of the 100 of these areas during that period.
- The proportion of residents bicycling to work increased in 85 out of 100 of America’s largest urbanized areas between 2000 and 2007-2011.
- The number of passenger-miles traveled per capita on transit increased in 60 out of 98 of America’s large urbanized areas whose trends could be analyzed between 2005 and 2010.
Perhaps the most interesting findings from the report arise when the economic performance of different cities over the past few years is compared with the average number of vehicle miles driven per person. You might expect that cities which have struggle economically over the past few years would have the biggest decline in per capita travel – because of higher unemployment, reduced business travel, generally less wealth to spend on cars etc. However, the report’s analysis actually shows the opposite is true:
What the data appears to be showing is that cities which experienced the greatest decrease in per capita VMT between 2006 and 2011 were the cities which fared best in terms of lower unemployment, higher median income and a lower level of increase in poverty.
The report’s authors make some pretty heavy hitting conclusions and recommendations for policymakers:
The study found that cities with the largest decreases in driving were not those hit hardest by the recession. On the contrary, the economies of urbanized areas with the largest declines in driving appear to have been less affected by the recession according to unemployment, income and poverty indicators.
“Government should support transportation initiatives that reflect these travel trends,” said Baxandall. “Instead of wasting taxpayer dollars continuing to enlarge our grandfather’s Interstate Highway System, we should invest in the kinds of transportation options that the public increasingly favors.”
I’m guessing that if someone were to study what is happening with the economy locally we would see some similar trends. Meanwhile Auckland continues to gear up for a giant spend-up on motorways.