Carbon dioxide (CO2) emission performance standards for new passenger cars in the European Union are indexed to vehicle weight. But the regulation defining the long-term target of 95 g/km to be met by 2020 ([EC] No. 443/2009) requires a review of the exact modalities for reaching this target, which creates the possibility of indexing performance standards to a different utility parameter than vehicle mass.
This paper assesses several potential index parameters, and uses an extensive database of 2009 sales of passenger cars in the European Union to analyze the effects of different target systems on manufacturers and individual vehicles.
The assessment indicates that a size-based emission target system offers several advantages over the current weight-based system. Under a size-based system emission reductions from vehicle weight reduction are fully taken into account, encouraging greater emission reductions and giving manufacturers more flexibility in meeting their targets at minimum compliance costs. Furthermore, a size-based target system is less prone to gaming and correlates better with vehicle utility than weight. When deciding between vehicle footprint or pan area (shadow) as an index parameter, footprint offers several advantages; in particular, footprint data is already systematically collected under the existing regulation (EC) no. 443/2009.
The analysis of different target schemes shows that differences in the required 2009–2020 emission reductions between the most likely versions of a weight and a size-based system amount to a maximum of 2–4 g/km for the main manufacturers. None of the major vehicle types would be overly penalized or preferred under any of the systems.
Based on these findings, the paper argues that vehicle size, and specifically footprint, should be substituted for mass as a utility parameter for meeting the 95 g/km target by 2020, as well as for future European Union CO2 emission targets.