Working Paper

Trailer CO2 Certification in the European Union

Trailers are a key component of the on-road freight transport system. Still, they have not yet been included in the regulatory measures aimed at reducing the CO2 emissions from the sector. Aware of this shortcoming, the European Commission has set a timeline to assess the inclusion of trailers in the scope of the future CO2 standards for new heavy-duty vehicles. The review of the future standards is expected for the year 2022.

The starting point of any policy measure designed to incentivize the development and deployment of trailer technologies for reducing CO2 emissions is the development of a certification methodology that captures their CO2 and fuel consumption benefits. This report analyzes the extension of the current CO2 certification procedure for heavy-duty vehicles, to also include trailers. To minimize the certification burden on trailer manufacturers, it is desirable to simplify the regulatory design as much as possible. Our analysis shows that these simplifications are possible without compromising the accuracy of the certification process. In particular we draw the following conclusions:

  1. The relative CO2 reduction with respect to a standard trailer can be used as the regulatory metric. This metric would simplify the regulatory design and would relax the specification requirements of the hauling vehicle used for certification.
  2. The majority of trailer share a common box geometry that makes them suitable for the use of aerodynamic devices. Trailers that do not have a box geometry (e.g., tankers of tippers) can still benefit from low rolling resistance tires and lightweighting. It is recommended on separating these two generic categories during the certification process.
  3. The current methodology for the determination of the aerodynamic drag of heavy-duty vehicles can impose significant burdens on trailer manufacturers. The use of computational fluid dynamics for the determination of the air drag reductions relative to a standard trailer would reduce the compliance cost on trailer manufacturers. 
  4. In comparison to full vehicle simulation using VECTO, the use of a linear trailer CO2 equation for the certification of trailers can reduce the administrative burden on trailer manufacturers, without sacrificing accuracy or compatibility with VECTO simulations. 

Related Publication: Market analysis of heavy-duty commercial trailers in Europe