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”).

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