Adjusting for vehicle mass and size in European post-2020 CO2 targets for passenger cars

Under European CO2 emission standards for passenger vehicles, individual manufacturer targets are adjusted by the average mass of the manufacturer’s fleet. The heavier the fleet, the higher the CO2 emissions target, and vice versa. This so-called limit value curve, using mass as the utility parameter, was built into the CO2 standards to maintain diversity in the vehicle market and to account for varying consumer needs.

When mandatory CO2 standards first came under discussion, a key argument for using mass as the utility parameter was data availability: mass data were readily available for all new vehicles in the market. However, with the introduction of the first CO2 standard, the EC was required to systematically collect data on alternative utility parameters and to evaluate the possibility of adopting a different one, specifically vehicle footprint. Vehicle footprint, a measure of the size of a vehicle, is the utility parameter used in greenhouse-gas vehicle standards in the United States. The second EU CO2 standard, introduced in 2014, reiterated that a change to vehicle footprint should be considered in future reviews of the regulation.

This briefing summarizes the implications of the current mass-based CO2 targets in the EU and outlines three alternative regulatory options:

  • Removing the utility parameter altogether
  • Using vehicle footprint instead of mass as the utility parameter
  • Keeping the mass utility parameter, but reducing its impact on manufacturers’ CO2 target

The discussion focuses on passenger cars (M1 vehicles), but similar concerns apply to light commercial vehicles (N1 vehicles, also referred to as “vans”).