Vehicle idling

Find out about the effects of vehicle idling on the environment and your health, and ways to reduce idling.

Idling occurs when a vehicle’s engine is running while it is parked or not moving.

Some idling, for example when you are stopped at a red light or in traffic, is unavoidable. However, many drivers idle unnecessarily while parked at a business, home, or school or at railway drop off and pick up zones.

Idling is not an offence, however, it is against the law to walk more than 3 metres away from your vehicle while the engine is running. 

Effect on the environment

Vehicles that run on petrol, diesel or gas use an internal combustion engine. When a vehicle’s engine is running it releases air pollutants and greenhouse gases, including particulate matter and carbon dioxide into our atmosphere. It also produces nitrous oxide and methane.

The primary vehicle emissions that impact air quality and health are particulate matter, especially fine particles (PM2.5) and nitrogen dioxide. Nitrogen dioxide and volatile organic compounds also contribute to the formation of photochemical smog which impacts air quality in some NSW cities and regions.

In 2021, road vehicles were the second largest source of greenhouse gases in NSW, contributing to climate change.

A 2021 study by Transport Energy/Emission Research estimates that Australians spend up to 21% of their total driving time idling. Modelling indicates that carbon dioxide emissions due to idling may equal the equivalent of an additional 1.5 million vehicles on the road across Australia each year.

Effects on human health

Idling increases the amount of air pollution. International and domestic research has found that some air pollutants, such as fine particulates (PM2.5), have potential health effects at any level and there is a higher risk of experiencing a negative health impact over a person's lifetime.

Some people are more vulnerable when exposed to air pollution. This includes Aboriginal People, people with pre-existing health conditions, unborn children and pregnant women, children, and the elderly.

When many drivers are idling in the same place, they can create an air pollution hotspot where air pollution is concentrated. These expose people to an increased risk of experiencing negative health effects from air pollution. Vulnerable people are most at risk.  

Impacts of short-term exposure to air pollution may include:

  • increased coughing, wheezing, and difficulty breathing
  • increased irritation to the eyes and throat
  • worsened asthma and other pre-existing respiratory conditions

Impacts of long-term exposure to air pollution may include:

  • increased risk of children developing asthma
  • increased risk of people developing heart disease and lung cancer
  • increased risk of miscarriage, early birth, and low birth weight
  • impaired development and function of the brain
  • shortened lifespan

The Sydney Air Quality Study found that vehicle emissions are the third highest human-made source of fine particulates (PM2.5), in terms of impacts on mortality and associated health costs from premature death or years of life lost.  Vehicle exhaust emissions account for an estimated $614 million, and non-exhaust emissions account for an estimated $218 million a year in health costs. 

See NSW Health for more information on the health effects of air pollutants in NSW.

Effects on your wallet

Reducing idling could save you money on fuel, maintenance costs and increase the lifespan of your vehicle.

Vehicles use fuel while they idle, the amount depends on the vehicle size, engine type, vehicle weight and age. Research shows that idling for more than 10 seconds burns more fuel than starting or turning off the engine.

Idling can also increase wear and tear on vehicles, increasing the frequency of oil changes and spark plug replacements and may reduce the life of your vehicle’s battery and engine.

Alternatives to idling

Any action you take that reduces idling helps improve the quality of our air and the health of our communities.

Alternatives to idling include:

  • if you stop for longer than 30 seconds, turn off your engine, unless you’re in traffic
  • do not idle to warm up your engine – modern vehicles no longer require this
  • ensure your ‘stop-start’ technology is enabled if it is installed in your vehicle
  • where possible consider alternative transport options, such as:
    • taking public transport, cycling or walking
    • carpooling with friends or rideshare
    • driving outside peak-traffic times
  • park while picking up takeaway instead of using the drive-through
  • open your vehicle’s windows, use a windscreen sunshield, or park in the shade on a hot day instead of running the engine to power the air conditioner
  • share this information with others to encourage them to reduce vehicle idling
  • switch to an electric vehicle if you can

Other initiatives to reduce emissions from vehicles

The EPA and NSW Government have developed a range of initiatives that aim to reduce emissions from vehicles. See Reducing motor vehicle emissions and Transport for NSW for more information.