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Transport VKT
Types of vehicles (vehicle kilometres travelled by vehicle type)
Larger, heavier vehicles have a greater effect on the environment than smaller, lighter ones. They tend to have bigger engines and are often diesel powered.
Current situation
In 2007, the light vehicle fleet – light passenger vehicles and light commercial vehicles – was responsible for 91.6 per cent of the total distance travelled. The remaining 8.4 per cent was contributed by heavy trucks and buses, and motor cycles.
Total vehicle kilometres travelled (VKT) by vehicle type in New Zealand, 2007
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Note: Data discrepancies between the text and this figure are due to rounding.
Data source: Ministry of Transport.
Long-term trend
There was an 11 per cent growth in light fleet travel between 2001 and 2007. However, combined, trucks and buses have grown by 23 per cent. Although these heavy classes only represent a small proportion of total VKT in New Zealand, they consume a disproportionately high amount of transport fuel, almost entirely diesel. This means that even a small increase in VKT travelled by the heavy vehicle classes leads to increase in greenhouse gas emissions and air pollutants harmful to human health.
VKT by vehicle type in New Zealand, 1990–2007
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Note: The gap in the data indicates a change in data collection methods. Before 2001, VKT data for light passenger vehicles, light commercial vehicles and motor cycles were collected together.
Data source: Ministry of Transport.
Road freight transportation
The majority of heavy vehicles travelling on New Zealand roads are freight vehicles. Growth in the economy tends to stimulate growth in road freight transport in the same way that it affects growth in total VKT.
Since the early 1990s, real GDP and road freight transport both increased. From an environmental perspective, it would be preferable for the economy (ie, GDP) to grow at a faster rate than the growth rate of road freight transport - also known as decoupling.
Road freight transport and real GDP in New Zealand, 1992–2007, 1992=100
Data source: Ministry of Transport and Statistics New Zealand.
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 road freight transport per unit of GDP. The green bars indicate decoupling, that is, real GDP has grown at a faster rate than road freight transport from one year to the next. This means that each dollar of productivity requires fewer tonne-kilometres of travel and therefore places less pressure on the environment.
Conversely, the red bars indicate that road freight transport grew at a faster rate than real GDP from one year to the next, and show a lack of decoupling.
Between 1992 and 2004 road freight transport increased by 101 per cent while real GDP increased by 56 per cent. This indicates that road freight transport grew at a faster rate than real GDP (as seen in the red bars), and hence placed greater pressure on the environment for each dollar of GDP produced.
In 2005 and 2006 road freight transport grew at a slower rate than real GDP. This indicates that road freight transport decoupled from GDP in this period, as seen in the underlying green bars. This trend was reversed in 2007 when, once again, road freight transport increased at a faster rate than real GDP.
There are some limitations to this decoupling measure. Because it only covers road freight transport, it does not capture shifts to other modes of freight transport such as rail or sea. Nor does it make allowance for more efficient loading of vehicles – for example, two tonnes carried by one truck puts less pressure on the environment than two loads of one tonne carried separately in two trucks.
Bus travel
Although buses only make up approximately 10 per cent of heavy-vehicle travel in New Zealand, between 2001 and 2007 there was a 36 per cent growth in bus travel. This potentially reduces the overall road transport pressure on the environment by reducing the number of private vehicles on the road.
Recent trend
The trend of increasing heavy-vehicle travel was not so pronounced in 2007. Between 2006 and 2007, light-fleet travel grew by 2.5 per cent, while truck and bus travel grew by 3 per cent. This means there was no significant change in the proportion of travel by each main vehicle type.
Motor cycle travel, which makes up less than 1 per cent of New Zealand’s VKT, is the exception. In 2007, there was an upsurge in motor cycle travel with an increase of 13 per cent in the motor cycle VKT, demonstrating that motor cycles have become an increasingly popular form of transport. This is also reflected by a 47 per cent increase in motor cycle numbers since 2003, although, at only 3 per cent, motor cycles remain a very small part of the whole vehicle fleet.
An increase in motor cycle numbers is important from both an environmental and human health perspective. New Zealand has no controls on the exhaust emissions from motor cycles. Increasing motor cycle travel could therefore lead to increased emissions of harmful pollutants, although this depends on the type of travel that the motor cycle is replacing.
What can you do?
- Help lower air pollution, fuel use and traffic congestion by leaving your car at home, especially for short trips – car engines use 20 per cent more fuel and produce up to 20 times the exhaust emissions when cold.
- Walking and cycling are ideally suited to short trips. It is good exercise and can save you money.
- Look out for walking school buses in your community to give your children a safe, sustainable way to travel to school.
This information has come from the environmental report card on vehicle kilometres travelled by road.
Move to next variable reported on for VKT: age of vehicles travelling.
Last updated: March 2009
