Skip to main content.

Environmental effects

Transport generates a number of adverse environmental effects from both transport infrastructure and vehicles. The effects can be direct, indirect and cumulative. Indirect effects may have greater consequences than direct effects, but are not generally well understood.

Transport infrastructure and the operation of vehicles can affect rural and community character, and can sever communities. Discharges and road crashes have a significant impact on health, and the form of the transport system can be a deterrent to exercise by walking and cycling.

The development of car-dependent environments imposes higher average living costs on families and can also restrict mobility for the elderly, children, the poor, the disabled and those who do not wish to own a motor vehicle.

Congestion also imposes some significant costs on communities. These include:

  • environment costs through higher levels of air pollution
  • economic costs – Auckland’s congestion is estimated to cost the national economy more than $1 billion per year
  • social costs, for example, increased levels of stress and less time available for other activities.

Emissions

Vehicle exhaust emissions are a major source of air pollution in some areas, particularly around busy road corridors. Pollutants include carbon monoxide (CO), nitrogen dioxide (NO2), benzene, and particulate matter.

Vehicle emissions affect people’s health, and a recent study estimated that 399 people will die prematurely each year because of vehicle air pollution.

Vehicles also emit carbon dioxide (CO2), which is a greenhouse gas. Transport is responsible for 44 percent of New Zealand’s carbon dioxide emissions, and around 16 percent of our total greenhouse gas emissions.

For more information visit the Climate Change section of this website.

Byproducts

Heavy metals and petroleum products from vehicles can contaminate the land and stormwater. Transport is also responsible for some of the extensive heavy metal contamination of some harbours and estuarine areas. Contaminated stormwater can make receiving water unsafe to swim in, drink, or collect shellfish. Culverts for transport infrastructure can disrupt fish migration. Suspended sediments, from road works for example, can affect water clarity, favouring species that prefer cloudy conditions.

Transporting hazardous substances carries a risk of spillage. Marine oil spills can devastate marine and coastal environments.

Expansion

Transport infrastructure (such as roads or parking spaces) covers 25-30 percent of land in most modern cities. Transport allows urban expansion, which can consume or damage valuable agricultural lands, natural habitats, and wahi tapu. Urban expansion can create inefficient travel patterns and congestion. Habitat fragmentation by roads or rail tracks can lead to biodiversity losses, and provide corridors for the spread of pests and weeds.

Many difficult waste streams are transport-related. These include end-of-life vehicles, tyres, and oil. Used oil is New Zealand’s largest non-aqueous liquid waste (at 30 million litres a year). Older air conditioning systems may contain ozone-depleting CFCs, while newer ones mainly have HFCs, which are greenhouse gases.

Biosecurity

Transport can increase biosecurity risks. As well as undesirable goods and people, international travel and trade can allow new organisms or diseases to enter New Zealand. Organisms and diseases can also spread within New Zealand with the assistance of transport – either via the transport of stocks or goods, or by vehicle movements. Roads and rail tracks also provide a corridor for organisms to travel.

Noise

Noise and vibrations can affect people who live or work near busy roads, rail facilities, ports and airports, or under flight paths. This can cause stress, exacerbate existing medical conditions and interfere with daily activities such as communicating or sleeping. High levels of noise can depress property values.

Last updated: 17 September 2007