NOx and particulate emissions from buses are proportionally high in many UK urban areas. Within such areas, targeting bus fleets to attain emission reduction may be one of the most cost effective measures within action plans. There are a number of emission reduction strategies to target buses, centred around managing the movement of buses more effectively and by increasing the Euro standard of buses, which lowers NOx and PM emissions. Policy tools include:

  • Tendered services, where a local authority subsidises routes that are not commercially viable. In such cases a Euro Standard condition may be included in the contract.
  • Traffic Regulation Condition, where a local transport authority can apply to the Traffic Commissioner for a Traffic Regulation Condition (TRC) under section 7 of the Transport Act 1985. This can be used to restrict any class of vehicle (including buses) from using any road. The local authority must demonstrate that the TRC would reduce or limit air pollution. If an operator does not comply with a TRC then enforcement action can be taken by the Traffic Commissioner. Oxford City Council have placed a TRC to create a low emission zone which applies to buses operating along routes into the city. All buses had to comply to Euro V by 1/1/2014. More details about this can be found on the Low Emission Zones in Europe website.
  • Quality Partnerships, which is an agreement between a local authority and bus operators to improve services along specified routes. They may be voluntary or statutory. The Local Transport Act 2008 means the creation of these more straightforward. More information on their implementation and case studies can be found on the Bus Partnership website.


Defra has published Practice Guidance Notes on measures to encourage the uptake of low emission vehicles and retro-fitted abatement equipment. These set potential options for schemes and summarise the legal basis for implementation and enforcement. They also describe how to develop and quantify the potential benefits of such schemes, including worked examples.

There are also a series of review and case study documents provided below which cover the following:

  • Various technologies and policies for reducing emissions of pollution from buses.
  • Methods for estimating carbon emissions from buses.
  • The Low Carbon Vehicle Partnership has produced a guidance note designed to assist local authorities to introduce low carbon buses using powers under the Local Transport Act.


Practice Guidance Notes

Released: February 2009 (PDF, 439 KB, 77 pages)

Review of Bus Fleet Compositions and Implications for Emissions Reduction Strategies

Released: April 2009 (PDF, 340 KB, 56 pages)

Scenarios and opportunities for reducing greenhouse gases and pollutant emissions from bus fleets in PTE areas

Released: March 2009 (PDF, 1 MB, 105 pages)

Carbon Footprinting of Policies, Programmes and Projects

Released: March 2009 (PDF, 1.06 MB, 91 pages)

Local Authority Transport Toolkit for Low Carbon Buses

Released: June 2012 (PDF, 8.7 MB, 56 pages)

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