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Transport VKT Total
Influences on vehicle kilometres travelled (VKT)
More people, more vehicles, more travel
Generally speaking, a growing population is accompanied by a growing number of vehicles. The population in New Zealand grew by 9 per cent or 343,700 people between 2001 and 2007. There was an 18 per cent growth in vehicle numbers between 2001 and 2007 – double the population growth.
As population grows, so too does the total distance travelled by road, unless balanced by a significant drop in the distance each person drives. This could occur if freight transport and discretionary travel reduced (for example, if the economy contracted significantly) or there was a widespread shift to other transport options, such as public transport, walking or cycling.
There is an increasing number of vehicles for each person in New Zealand. In 2007, there were 70 light vehicles for every 100 New Zealanders, compared to 64 in 2001. Generally speaking, such an increase leads to increased access to transport, an increase in total VKT and can lead to greater congestion on our roads. More greenhouse gas emissions are produced for each kilometre travelled on congested roads. In 1996, 45 per cent of New Zealand households had access to two or more vehicles. By 2006, this figure had risen to 54 per cent. Greater vehicle numbers also lead to greater waste in terms of used oil, batteries, tyres and greater numbers of scrapped vehicles.
Increases in individual travel can also affect VKT. While changes at the individual level may appear small, they can have a significant cumulative impact. The average distance travelled per person on New Zealand roads (VKT per capita) fluctuated between 2001 and 2007, but was 3 per cent higher in 2007 than in 2001.
Population, total number of vehicles and VKT in New Zealand, 2001–2007
| Population growth since 2001 | Growth in total vehicle numbers since 2001 | Growth in total VKT since 2001 | Growth in travel per capita since 2001 | |
|---|---|---|---|---|
| 2001 | 0.00% |
0.00% |
0.00% |
0.00% |
| 2002 | 1.51% |
2.09% |
2.91% |
1.38% |
| 2003 | 3.32% |
5.66% |
5.95% |
2.55% |
| 2004 | 4.66% |
9.46% |
8.92% |
4.07% |
| 2005 | 5.61% |
13.43% |
10.02% |
4.18% |
| 2006 | 7.85% |
15.82% |
9.16% |
1.21% |
| 2007 | 8.96% |
18.40% |
11.97% |
2.76% |
Data source: Ministry of Transport.
A growing economy
Over the past few years, the high New Zealand dollar and economic growth are likely to have contributed to both increasing vehicle numbers and VKT.
Gross domestic product (GDP) is an indicator of economic growth. By comparing trends in both real GDP and vehicle kilometres travelled on New Zealand roads, we can study the relationship between economic growth and transport activity. Typically, a more buoyant economy encourages greater travel for business and recreation.
Since the early 1990s, real GDP and total VKT have both increased. From an environmental perspective, it is preferable to see the economy (ie, GDP) grow at a faster rate than the growth rate of VKT (ie, for a drop in VKT per unit of GDP to occur). This is called decoupling – the growth rate of an environmental pressure (eg, VKT) is less than that of its economic driving force (eg, GDP).
Total VKT and real GDP in New Zealand, 1992–2007, 1992=100
Data source: Ministry of Transport and Statistics New Zealand.
Note: VKT data was collected differently before 2001. Data collected before 2001 cannot be directly compared to data collected after this date.
The right axis in the above graph reports the annual decoupling factor. It is calculated as the percentage change from one year to the next in VKT per unit of GDP. The green bars indicate decoupling, that is, real GDP has grown at a faster rate than total VKT from one year to the next. This means that each dollar of productivity requires fewer vehicle kilometres of travel and therefore places less pressure on the environment.
Conversely, the red bars above indicate that total VKT grew at a faster rate than real GDP from one year to the next, and show a lack of decoupling.
Between 1992 and 2000, total VKT and real GDP increased at a similar rate. The lack of decoupling seen in figure 3 in 1997 and 1998 was largely influenced by the Asian financial crisis which affected GDP at that time.
Between 2001 and 2007, total VKT increased by 12 per cent while real GDP increased by 22.5 per cent. This indicates that VKT decoupled from GDP year-on-year, as seen in the underlying green bars. The decoupling factor in 2007 was lower than previous years, which makes it difficult to predict future trends.
There are some limitations to this decoupling measure. Because it only covers road transport, it does not capture shifts to other modes of transport such as rail or air, nor does it make allowance for the fact that not all travel is economically motivated but occurs for social and other reasons.
This information has come from the environmental report card on vehicle kilometres travelled by road.
Return to total VKT page.
Last updated: March 2009
