As part of the decarbonisation process for passenger car fleet in Austria, battery electric cars in particular have been subsidised in recent years, as these vehicles are considered to be largely emission free during use and are expected to reduce emissions in future. However, in order to sustainably reduce the global greenhouse gas emissions of Austrian passenger car traffic, taking into account all types of fuel systems, it is necessary to apply a cradle-to-grave approach, as is commonly done in comparable analyses in the literature, which evaluates the emissions of the entire vehicle life cycle. The most important phase in the life cycle assessment remains the well-to-wheel phase, which includes emissions from energy supply and vehicle use. Due to the large number of influencing factors, highly simplified models are usually used for this phase in the literature. As part of this work, a methodology was developed that, allows an in-depth analysis of entire vehicle fleets by linking real vehicle movements with emissions data and energy consumption. By using real vehicle movements, environmental conditions (ambient temperature, etc.) and traffic situations (traffic jams, etc.) can be integrated into the emissions assessment. To capture the influencing factors more realistically, the assessment is performed at hourly rather than annual time intervals, unlike most previous studies. This new approach provides therefore a more detailed and realistic cradle-to-grave analysis of the Austrian passenger car fleet, making it possible to test individual measures in future scenarios and to define a coordinated strategy for minimizing the fleet’s future global greenhouse gas emissions.