Future policy analysis, total NO<sub>X</sub> and CO<sub>2</sub> emissions from cars, 2015-2050

The 'Dieselgate' emissions scandal has highlighted long standing concerns that the performance gap between 'real world' and 'official' energy use and pollutant emissions of cars is increasing to a level that renders 'official' certification ratings virtually ineffective while misleading consumers and damaging human health of the wider population.

New research by the ECI's and TSU's Christian Brand applied a bespoke disaggregated model of the transport-energy-environment system (the UK Transport Carbon Model) to explore the impacts of retrospective and future policy scenarios on the UK car market, trade-offs between greenhouse gas and air quality emissions, and changes in future fuel use and associated tax revenues.

It found that the impacts on human health of 'real world' excess NOX emissions in the UK are significant. Future 'low diesel' policies can have significant air quality benefits while showing few (if any) carbon disbenefits, suggesting future car pricing incentives may need to be rebalanced taking more account of effects of local air pollution (as has been suggested for London). Car pricing incentives are however unlikely to transform the car market on their own. As the modelling suggests future policy will have to go the extra mile (pun not intended) by promoting additional market changes, industry push, infrastructure investment and policy pull in order to achieve the emissions savings, 'co-benefits' and avoided damage costs of a range of pollutants required to meet climate, air quality and health damage goals.

This research was funded by the EPSRC (Grant No. EP/L024756/1) as part of the Decision Making Theme of the UK Energy Research Centre Phase 3.