Low Emission Zone - Feasibility Study

We have undertaken a study into whether a Low Emission Zone (LEZ) should be introduced in Sheffield. 

The aim of the LEZ would be to help our partners and us to comply with European Union Air Quality standards for NO2 and PM10. This would be by tackling the main traffic-related emissions which are contributing to the current air quality problems in the Sheffield area.

The aim of the LEZ study was to work out the potential costs, benefits, air quality impacts, emissions reductions and timescales for bringing about a LEZ in Sheffield.

The study was carried out in 2 phases.  The work was funded by the Department for Environment, Food and Rural Affairs (DEFRA) and led by us.

A Steering Group was appointed to oversee the study.  As well as ourselves, there were representatives from the following organisations:

  • South Yorkshire Passenger Transport Executive (SYPTE)
  • South Yorkshire Local Transport Plan Partnership (SYLTP)
  • First Group
  • Stagecoach
  • TM Travel
  • Freight Transport Association (FTA)

Phase 1 Study

The Phase 1 Study was completed on 9 November 2012 and provides an initial assessment of transport emissions only, and the main contributors to these emissions, including the likely impact of improvements to the vehicle fleet by 2015.

Phase 1 has highlighted the importance of using the correct assumptions when estimating and forecasting transport related emissions.

  • UK Government (DEFRA) v European (COPERT) emission factors produce significantly different results.
  • The assumptions about the age, engine category and fuel type of the vehicle fleet has a significant impact on the forecast levels of emissions.
  • Increasing diesel proportions is a major issue.

Phase 1 has also concluded that any potential interventions that are aimed at one vehicle type alone are unlikely to remove all of the air quality problems resulting from transport emissions.

Phase 2 Study

The main aim of the Phase 2 Study was to further refine the assessment work undertaken in Phase 1.  This was done to provide evidence to develop an Air Quality Strategy that will support the new Low Emission Zone (LEZ).

The Steering Group overseeing the study in Phase 2 also included the Road Haulage Association (RHA) and the Institute for Transport Studies (ITS).

The 'Low Emission Zone (LEZ) Feasibility Study' Phase 2 Report has been produced - see below.


These are the recommendations from the study only (they are not our policy):

  1. Minimum NOx emission standard (EURO VI) for buses
  2. Maximum NOx emissions rate levels for:
    • Taxis – affecting the ‘worst polluting’ 50% of the current fleet
    • Light Goods Vehicles (LGV < 3.5T) – affecting the ‘worst polluting’ 15% of the current fleet
    • Other Goods Vehicles (OGV > 3.5T) – affecting the ‘worst polluting’ 10% of the current fleet
  3. Measures to encourage 10% of private car users to switch from diesel back to petrol
  4. 5% reduction in emissions from both petrol and diesel private cars, by reducing car use, encouraging more-efficient driving styles and promoting travelling at different times
  5. 5% reduction in emissions from Other Goods Vehicles (OGVs > 3.5T) by more efficient routing and driving styles

Further work is now required to analyse the costs and benefits of the Study recommendations.  The Air Quality Action Plan will then be reviewed and updated.