What policies are effective at reducing carbon emissions from surface passenger transport?

This report examines the merits of a range of different policies that offer the prospect of CO2 emissions reduction from road transport.

The report therefore has the following objectives:

  • Review the evidence for CO2 emission reduction potential and cost-effectiveness across policies that target car technology/choice and those that target wider travel choices
  • Identify the key issues and problems associated with each policy type
  • Identify whether and where policies are complementary or synergistic
  • Identify evidence gaps and highlight future research needs
  • Draw conclusions relevant to current UK policy

The report does not undertake new modelling or empirical research; rather it provides a thorough review of the current state of knowledge on the subject, guided by experts and in consultation with a range of stakeholders.

The project team undertook a systematic search for every report and paper related to the assessment question.

Experts and stakeholders were invited to comment and contribute through an expert group. A team of expert consultants was commissioned to categorise, review and distil the evidence. This tightly specified search revealed over 500 reports and papers on the subject, each of which was categorised and assessed for relevance.

Evidence Tables

Annex 2 of the main report described the evidence gathering and analysis process that the project team adopted. The first step of this process was to assess what the evidence base had to say about each type of policy.

The project team considered 36 policy types and the evidence for each one was collated into one ‘policy record’ document per policy type. Each piece of evidence was analysed in terms of its relevance to one or more policy type. Information was then extracted and placed in the appropriate policy records. Once the project team had reviewed all the evidence and captured the relevant data, each policy record was distilled and concentrated, drawing out principal findings and arguments.

The distilled policy records were the key resource for the project team during the analysis stage and they constituted the primary material supporting the findings of the report. The project team felt that the records provide invaluable material and links to the wider evidence base, and that it was appropriate to make the material available as a research resource.

To this end, the distilled policy records have now been converted (and in some cases, merged) into ‘evidence tables’ to provide a more accessible way of presenting the information. Each of these evidence tables are provided below: