The European Commission is responsible for planning, preparing and proposing new European Union (EU) laws and policies. It does so based on evidence and backed up by the views of citizens and stakeholders. In its Better Regulation Guidelines, the European Commission sets out the principles that it follows when preparing new initiatives and proposals and when managing and evaluating existing legislation: Applying the principles of better regulation will ensure that measures are evidence-based, well designed and deliver tangible and sustainable benefits for citizens, business and society as a whole. As the science and knowledge service of the European Commission, the Joint Research Centre's (JRC) mission is to support EU policies with independent evidence throughout the whole policy cycle. The JRC’s Sustainable, Smart and Safe Mobility Unit aims to give scientific/technical support to the development of Commission policies in the field of low-carbon technologies for transport, through laboratory experiments in its test facilities and through modelling tools. One of these modelling tools is the JRC’s DIONE model, which has been developed since 2014 to support EU road transport decarbonisation policies. The model can be employed to calculate the impacts of more stringent new road vehicle CO2 standards on the total costs of ownership of vehicles from the point of view of users as well as the society. In the last few years, the model has supported four EC impact assessments. This supports, among others, evidence-informed policymaking, promoted as tool no.4 in the EC’s Better Regulation Toolbox. Evidence used for policymaking should be handled in a transparent way: Whenever possible, the evidence collected and used should be FAIR, meaning it is findable, accessible, interoperable and reusable. (…) FAIR principles help managing scientific evidence transparently. Making evidence FAIR ensures that studies, data, but possibly also code of models, protocols applied and other research resources, are as far as possible findable by anyone using common search tools; accessible so that the data and metadata can be examined; interoperable so that comparable data can be analysed and integrated through the use of common vocabulary and open formats; and reusable by other researchers or the public as a result of robust metadata, provenance information and clear usage licences. Along these lines, increasing the findability, accessibility, interoperability and reusability of the DIONE model makes a contribution to better EU regulation. The JRC has therefore decided to document the model, and make one of its modules reusable for researchers and the wider public.
