Tackling stationary engine idling

Reducing emissions from road transport is one of the most effective ways we can improve our air quality. Turning off your engine when you’re parked can help make a positive difference. It can also save you fuel and money. 

It is an offence to leave your engine running. You could receive a fine of up to £150 for doing so from 30 September 2026. 

Rule 123 of the Highway Code says that drivers should apply the parking brake and switch off the engine when their vehicle is stationary on a public road.

• Engine idling creates air and noise pollution which is harmful to public health. Every minute a car engine is left idling, it produces enough exhaust to fill up to 150 balloons with harmful pollutants, including cyanide [1]. 
• Idling contributes to a range of health problems including heart and lung diseases. Short term exposure to elevated air pollution can cause immediate health effects, while long term exposure is linked to reduced life expectancy [2].  The Royal College of Physicians estimates that air pollution could be linked to around 30,000 deaths in 2025 in the UK.
• Children, young people and people with existing health conditions are particularly vulnerable. Research has shown that pollutant concentrations are often higher near ground level [3].  Babies in pushchairs, young children, people using wheelchairs or mobility scooters, and other vulnerable groups may therefore face increased exposure in areas where engines are left idling [4]. 
• Idling wastes fuel and can affect people inside the car, as well as outside. Air quality inside a vehicle can be as poor as, or worse than outside, particularly when stationary near other idling vehicles [5]. Idling for an hour can waste half a gallon (two and a quarter litres) of fuel or more. [6]

When your vehicle is parked for more than two minutes, please remember to switch off your engine. We recognise that there may be occasions when you may need to idle your engine:

• If your engine appears to have a fault and needs to be running for diagnostic or maintenance purposes
• If your vehicle is stationary because of traffic.

Examples of when it is not acceptable to leave your engine running:

• If you’re waiting to pick up or drop off passengers
• If you’re charging a phone or listening to music
• Using heating or cooling systems for comfort.

Many people are not aware that stationary idling is an offence. We are raising awareness and encouraging drivers to switch off to save money and keep our air clean. 

We are also replacing the current £20 fixed penalty fine with a higher penalty range of £75-£150 from 30 September 2026. This will reflect the serious consequences of air pollution.

1. ‘Engine Off Every Stop’ campaign by Idling Action London
2. Air pollution and health in Wales factsheet by Public Health Wales,
   Air pollution guidance by Public Health England, 
   Web article: ‘Air pollution linked to 30,000 UK deaths in 2025 and costs the economy and NHS billions, warns Royal College of Physicians’
3. Scientific journal article: ‘Maximum ground level concentration of air pollutant’ by Embaby, Mayhoub, Essa and Etman, Atmósfera 2002, 15(3)
4. Scientific journal article: ‘A review of factors surrounding the air pollution exposure to in-pram babies and mitigation strategies’ by Sharma and Kumar, Environment International, Volume 120, 2018, 
   Web article: ‘Air pollution: A threat to children's rights’ by UNICEF, 
   Web article: ‘How air pollution affects your child's lungs’ by Asthma + Lung UK
5. Pollution and air quality information by Cheshire West and Chester Council
6. Air quality and air pollution information by the London Borough of Merton