What are they?

Low Emission Zones (LEZ) and Ultra Low Emission Zones (ULEZ) are essentially a system of local road charging or regulation, usually in urban areas, designed to improve air quality and reduce congestion. They do this by targeting vehicles which emit high levels of fine particles (‘particulate matter’ or PM) and nitrogen dioxide. This is measured on the Euro emission standards.

The intention is to encourage individuals and businesses (who bulk purchase vehicle fleets, goods vehicles and passenger vehicles) to choose cleaner vehicles. An LEZ can either charge higher polluting vehicles to come into the zone or ban them completely.

While London has gone down a comprehensive route applying to a wide range of vehicles, and is proposing extending it to cars by 2020, there are LEZ-style initiatives in other English cities focused on reducing bus emissions (Brighton, Oxford, Norwich, Nottingham).

How are they introduced?

In England (outside London) and Wales the relevant legislation is Part III of and Schedule 12 to the Transport Act 2000, as amended by Part 6 of the Local Transport Act 2008. This provides for the introduction of road charging outside London. Charging schemes may only be made “if it appears desirable for the purpose of directly or indirectly facilitating the achievement of policies in the charging authority’s local transport plan”.

In London, the relevant legislation is section 295 of and Schedule 23 to the Greater London Authority Act 1999, as amended by Part 6 of the Local Transport Act 2008.

In Scotland, the relevant legislation is Part 3 of the Transport (Scotland) Act 2001, as amended. Any Scottish scheme requires the consent of Scottish Ministers.

How does the London LEZ work?

The LEZ covers most of Greater London. To drive within it without paying a daily charge, a vehicle must meet certain emissions standards (i.e. Euro 3 for larger vans and minibuses and Euro 4 for lorries, buses and coaches) that limit the amount of particulate matter coming from its exhaust. If a vehicle does not meet the LEZ emissions standards, it can still be driven within the LEZ by paying a daily charge.

The LEZ applies to diesel lorries, buses, coaches, motor caravans, motorised horseboxes, larger vans, minibuses and other specialist vehicles.

The LEZ uses cameras to read vehicle number plates and check them against a database to see if they meet the required emissions rules.

The charges for those vehicles not meeting the relevant standard are either £100 or £200 depending on your vehicle.  The penalties for non-payment are either £250 or £500 if paid within 14 days or £500 or £1,000 if paid after that.

In February 2013 Mayor Johnson announced his intention to create an Ultra-Low Emission Zone (ULEZ) in central London from 2020. TfL issued a consultation on this in October 2014. The ULEZ proposals would require vehicles travelling in central London to meet Euro 6 (HGVs, buses and coaches and diesel cars, vans and minibuses), Euro 4 (petrol cars, vans and minibuses), or Euro 3 (motorcycles and similar) emissions standards.

How effective are they?

Information from the GLA London data store show that results have been mixed in London. While there has been a reduction in PM, levels of nitrogen dioxide have not fallen significantly.

Evidence from other European cities shows:

  • Berlin – 58% reduction of diesel particles, 20% reduction in NOx; reduction in PM10 exceedences of the relevant EU air quality standard from 28 to 24 per year, diesel particulate concentrations by 14-22%, and PM10 concentrations by 3% on main roads;
  • Cologne – results from the first year of operation show that air quality concentrations reduced more than the surrounding background: for NO2 by 1.2 μg/m3 (microgram per metre or air squared) (background reduction was 0.5μg/m3), PM10 by 4 μg/m3and 17 exceedences of the limit value (background reduction 4 μg/m3 and 7 exceedences); and
  • Stockholm – concentrations of PM02 were reduced by between 0.5 and 9%.

How are LEZs linked to wider air pollution targets?

Both short-term and long-term exposure to air pollution have adverse health effects.

Pollution from road traffic, and especially diesel engines, is the most significant cause of poor air quality, responsible for up to 70% of air pollution. In England, local authorities are responsible for managing air quality at a local level.

The need to improve air quality is recognised in EU legislation. As part of this Member States were required to prepare adequate plans to reduce are range of air pollution including particulates and nitrogen dioxide (NO2). These required the level of NO2 to be brought down to acceptable levels by 2015 at the latest.

The UK failed to do so and in most cases will not be achieving targets until beyond 2020. As a result, in February 2014, the EU Commission began infringement proceedings against the UK. The Government’s failure also led to a prosecution by ClientEarth, who argued against the UK’s position that enforcement of air quality measures lay at EU level. The Supreme Court disagreed and ordered that the Government submit new air quality plans to the European Commission no later than 31 December 2015.

What changes can we expect at national level in the future?

Following the Court ruling Government published new Draft Air Quality Plans for consultation in September 2015. The document identified transport as the main contributor to air quality problems and set out measures already underway in the 38 non-compliant zones.  It also said it would publish a framework for the implementation of new Clean Air Zones in England in 2016. This will set a standard for vehicles to be used in existing and proposed LEZs, to ensure a consistent approach by local authorities. Vehicles not meeting the standard will be subject to a charge or other restriction. 

The proposals were criticised by campaigners as a ‘plan for plans by others‘, which passes responsibility to local authorities, without further funding or new powers. This is particularly pertinent because under the Localism Act 2011  the Government has discretionary powers to pass all or part of any fines on to local authorities deemed responsible for breaches of EU legislation. The previous Government wrote to all local authorities in March 2014 to inform them of the infraction proceedings and remind them of these powers.

Further reading

HC Library briefing paper Roads: charging in London, SN2044, 21 May 2012

Mayor of London, Cleaner Air for London: Progress report on the delivery of the Mayor’s Air Quality Strategy, July 2013

TfL press notice, “The Mayor and TfL consult on Ultra Low Emission Zone”, 27 October 2014

Defra, Draft Air Quality Plans Consultation, 12 September 2015 [closed 6 November 2015]

Urban Access Regulation in Europe, Low Emission Zones [accessed 11 November 2015]

Low Emission Partnership, Low Emission Hub [accessed 11 November 2015]


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