Vehicle emissions and engine idling
Checks, fines and advice to help improve local air quality
Vehicle emissions affect air quality and people’s health. To help reduce pollution, we carry out roadside vehicle emissions tests and enforce rules that prevent unnecessary engine idling.
If your vehicle is checked, or if you stop with your engine running when it does not need to be, you could receive a fixed penalty.
Roadside vehicle emissions testing
We carry out roadside emissions tests to check that vehicles meet legal emission limits. These tests help identify faults that may cause harmful pollution, even if a vehicle has a valid MOT.
The test is carried out by trained staff and usually takes no more than 10 minutes. You may be asked to briefly rev your engine. If this is not suitable for your vehicle, tell the examiner before the test begins.
If your vehicle does not pass the initial test, a fuller check may be carried out. We aim to keep any delay to a maximum of 30 minutes in total.
Emissions test failures and fines
If your vehicle fails the full emissions test, you may receive a fixed penalty of £60, rising to £90 after 28 days.
The penalty will be cancelled if you can show, within 14 days, that the problem has been fixed and the vehicle now meets emission standards. You are responsible for the penalty even if you are driving someone else’s vehicle.
Engine idling offences
You must not leave your vehicle engine running when it is not needed. If you do, you may receive a £20 fixed penalty.
As a guide, if you are parked for more than 30 seconds, switch off your engine and restart it when you are ready to move. This uses less fuel, reduces pollution and improves local air quality.
When idling rules apply
The rules apply to all vehicles on public roads, including cars, buses, taxis and commercial vehicles. They do not apply when:
- you are stopped in traffic or at lights
- the vehicle is under test or repair
- you need to clear ice or mist from your windscreen in very cold weather
Find out more
Contact us if you want advice about emissions testing or engine idling rules.