HBEFA 5.1 – Use in Expert Assessment Work

We have prepared the Handbook of Emission Factors HBEFA 5.1, published in October 2025, for our expert assessment work.

For the preparation of expert reports, it was necessary to process the complex emission factor information from HBEFA 5.1 so that it can be combined with data from traffic counts, traffic forecasts and local site data and fed into emission and dispersion calculations. This processing was carried out in our office, and thus applicable emission factors are now available in 5-year steps.

With immediate effect, we are able to calculate vehicle emissions for our clients using the latest emission factors, which are required for the preparation of air pollutant assessments for planning approval procedures for motorways and roads as well as for clean air action programmes or clean air plans in accordance with the EU Directive on ambient air quality and cleaner air for Europe (2024/2881).