How low emission zones work

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The Transport Scotland Act 2019 provides the legislation to enable the creation and civil enforcement of low emission zones.

The national standards for low emission zones – such as emission levels, penalties and exemptions – will be set in regulations currently in development and due to be published later in 2020. Local authorities will then use these regulations to design each low emission zone based on their specific, local requirements.

It is proposed that:

  • low emission zone entry will still be based on the Euro emission engine classification standards – the proposed minimum criteria is:
    • Euro 6/VI for diesel vehicles
    • Euro 4/IV for petrol vehicles
    • Euro 6/VI for heavy-duty diesel engine vehicles including older retrofitted vehicles which would be improved to operate as Euro 6).
  • low emission zones operate continuously, 24 hours a day, seven days a week, all year round
  • enforcement will utilise Automatic Number Plate Recognition (ANPR) cameras, linked to a national vehicle licencing database, to monitor vehicles driving in a low emission zone and to detect vehicles which do not comply with the minimum Euro emission standards
  • low emission zones will be based on a penalty notice approach to discourage non-compliant vehicles from driving in the zone
  • the design, implementation and operation of low emission zones will involve grace periods to allow commercial fleet operators and private vehicle owners time to prepare
  • exemptions will be specified in regulations
  • local authorities publish a report annually on the effectiveness of low emission zones.

Euro emission standards

While the Transport (Scotland) Act 2019 does not set the mandatory vehicle emissions standards for driving in a low emission zone, it does set provisions for Ministers to create such regulations, which are expected to be published in 2020.

The consultation titled ‘Building Scotland’s Low Emission Zones’ outlined proposals for the minimum emission standards for low emission zones to be Euro 4/IV for petrol engines (generally vehicles registered from 2006) and Euro 6/VI for diesel engines (generally registered from 2016). The use of Euro standards in this manner is commonplace across European low emission zones.

A basic vehicle registration checker is available on this website:

The current proxy is to use vehicle age as a guide to the corresponding Euro classification, noting the dates when each Euro category was introduced.

  • The Euro 6 standard for diesel cars was introduced in September 2014, with any new car sold after September 2015 having to meet this standard.
  • The Euro 4 standard for petrol engines was introduced in January 2005, with any new vehicles sold after January 2006 having to meet this standard.

Support for bus operators

The Scottish Government has made an additional £8.85 million available in 2019/20 for the Bus Emission Abatement Retrofit Fund (BEAR) to support its commitment to introduce low emission zones into Scotland’s four biggest cities by 2020. Launched in 2018, this year marks the third round of funding to support micro and small bus operators with the financial costs associated with engine and exhaust retrofitting. There has been £1,577,701 in grants issued to eight bus operators in relation to 124 buses to date.

This technology helps reduce nitrogen dioxide emissions from older buses to achieve the Euro VI emission standard, which is the equivalent of a new, modern bus, through the installation of accredited retrofit technology.

In addition, the Scottish Green Bus Fund (SGBF) has supported 475 LEZ compliant buses into the fleet through £17.2m in Scottish Government funding across eight annual rounds.

The fund aimed to encourage more low carbon emission buses onto Scotland’s roads.

Operators of low carbon buses also remain eligible for an enhanced rate of the Bus Service Operators Grant which further incentivises the uptake and use of green buses – click to find out more about the Bus Service Operators Grant.

The Scottish Green Bus Fund has been replaced with the Scottish Ultra-Low Emission Bus Scheme. The Scottish Ultra-Low Emission Bus Scheme builds on the eight rounds of the Scottish Green Bus Fund, held each year between 2011 and 2018. The new fund will increase the level of environmental protection, improve air quality, and support the acceleration of uptake of the lowest emitting bus technology in support of emissions targets. Read more about the new scheme here.

Support for business/members of the public

The Scottish Government is committed to supporting the move towards cleaner, low carbon modes of transport. Further information on LEZ support funds are available at:

In the Programme for Government for 2018-19 – Delivering for Today, Investing for Tomorrow – the Scottish Government committed to help those who will have the most difficulty in making the transition to a low emission zone by creating a support fund that will target specific cohorts of both commercial and private vehicle owners affected by the introduction of the zones in Scottish cities’.

Various grants and loans are additionally available via the Energy Saving Trust.