The so-called CO₂ guideline contains information on the fuel and electricity consumption and CO₂ emission values of all passenger cars offered in Germany. It provides a basis for comparing vehicles. The provision of the guideline is prescribed by the Directive on Energy Consumption in Cars (Passenger Car EnVKV). The Association of International Motor Vehicle Manufacturers and the Association of the Automotive Industry have therefore commissioned Deutsche Automobil Treuhand (DAT) to prepare this guideline.

The new edition 2019 of the CO₂ guideline was necessary for the reference work to remain in conformity with the regulations. According to the current Directive on Energy Consumption Labelling (EnVKV), the published data may not be more than one year old. The CO₂ guideline from 2018 therefore loses its validity.

Originally, an amendment to the passenger car EnVKV with a conversion to the listing of values in accordance with the WLTP (“Worldwide harmonized Light vehicles Test Procedure”) test procedure was expected for spring 2019. Since this amendment by the responsible federal authorities is not yet foreseeable, the guideline had to be newly prepared and printed on the basis of the still valid EnVKV.