Proposal to promote harmonisation in use of reference fuels for testing, including hydrogen fuel, based on the following justifications:

1. The use of test fuels is permitted for certification testing of gaseous and particulate pollutants and power/smoke testing in Europe. However, other countries that have adopted and referenced UN R85 may not allow this. In this case, manufacturers have to prepare fuels with different characteristics, which is costly and requires a long time due to the current inconsistent situation.
2. We believe that the use of test fuels for gaseous and particulate pollutant measurement tests should be a priority as a precondition for the introduction of more stringent emission levels.
3. Hydrogen fuelled vehicles are covered in UN Regulation No. 83, but hydrogen is not yet covered in UN R49 and UN R85.
4. Hydrogen fuelled engines could be one complementary option to reduce CO₂ emissions of future heavy-duty vehicles.
5. Therefore, hydrogen fuel should be integrated in UN R49 and UN R85 for better alignment with UN R83.