See chapter 1, ‘Environmental reporting’ for more information on the core national environmental indicators and how they are used.
Vehicle kilometres travelled
The national environmental indicator for transport provides information on vehicle kilometres travelled (VKT) by road.
The report on the indicator derives its data from measurements of the following:
vehicle kilometres travelled by vehicle type (cars, light commercial vehicles, heavy commercial vehicles, and motorbikes)
vehicle kilometres travelled by vehicle age
vehicle kilometres travelled by fuel type (petrol or diesel).
The characteristics of our vehicles, such as age and type, and the distance we drive them determine the pressures on the environment. We use the ‘vehicle kilometres travelled’ indicator to identify changes in the composition and use of New Zealand’s vehicle fleet and to determine how these changes may be affecting the environment. Improving the vehicle fleet’s environmental performance is one way to reduce the pressures transport places on our environment.
Limitations of the indicator
The ‘vehicle kilometres travelled’ indicator only accounts for kilometres travelled by road vehicles. It excludes rail, sea, or air transport modes, which also have impacts on the environment.
The indicator does not take traffic congestion into account. Therefore, it is not possible to assess the proportion of vehicle kilometres travelled during peak traffic, when congestion leads to greater fuel consumption and exhaust emissions per kilometre travelled than during off-peak traffic.
The indicator does not take into account improvements over time in fuel quality or emissions reduction technology when it compares vehicle kilometres travelled year on year.
As the ‘vehicle kilometres travelled’ indicator accounts only for road transport, this chapter presents a wider picture of transport in New Zealand by using:
vehicle ownership rates to show the average number of vehicles owned per person in New Zealand
the 2006 Census of Population and Dwellings to show our use of motorised vehicles for travel to work, and the extent to which we use other modes of transport (for example, public transport, walking, and cycling)
information on the average engine size of vehicles used on New Zealand roads
records of international passenger arrivals and departures for all modes of transport
information about public transport.