Emissions Testing

The annual MOT test, required for every vehicle over three years old, includes the measurement of emissions carried out by authorised examiners. Roadside emission testing may be used by local authorities in England and Wales which have declared a traffic-related air quality management area (AQMA) under s.83 of the Environment Act 1995; this power is extended to all local authorities in Scotland, whether or not they have declared an AQMA. Under these provisions, authorised personnel may carry out a roadside test. If emissions exceed the permitted level a fixed penalty notice may be issued, or the driver may be asked to produce a certificate demonstrating that the problem has been rectified. Several authorities, or groups of authorities, have implemented programmes, and more plan to do so.

There are three principal concerns about the effectiveness of the system:

  • because of its relative simplicity, there is concern that the MOT test does not reflect a vehicle’s emission performance when it is actually used on the road;
  • a vehicle’s emissions can increase between the annual snapshots that the MOT test provides, and vary over relatively short periods;
  • current roadside emission checks have been introduced somewhat hesitantly by the Authorities, and, as currently operated, there are doubts about their effectiveness (and cost effectiveness) on such grounds as the cost of police time and concern about the implications of stopping vehicles.

In a research project funded by The BOC Foundation, we worked with consultants TRL to review the evidence and make recommendations. The reports are available in our members area.

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