This study aims to determine the fuel economy of a hydrogen vehicle by analyzing its energy efficiency in real road conditions. The object of the study is a fuel cell vehicle. Hyundai NEXO, in which hydrogen is an energy carrier, from which electrical energy is obtained for the drive. The purpose of the development is to determine the hydrogen consumption and the corresponding energy intensity (kWh/km) in different driving modes, as well as to analyze the influence of speed, driving dynamics and road conditions on the efficiency of the vehicle. The experimental study is carried out in a real road environment on the territory of Sofia and the adjacent expressways. Two main road cycles are defined: urban and mixed, which reflect the typical modes of operation of cars. A GPS-based system for measuring dynamic parameters is used to collect data, and hydrogen consumption is determined by the vehicle's on-board instruments. The assessment of economy is carried out using indicators such as hydrogen consumption (kg/100 km) and energy consumption (kWh/km), which allows comparison between different driving modes. Particular attention is paid to the influence of different speeds on energy efficiency, as well as the differences between urban and extra-urban traffic. The results obtained contribute to a detailed study of the real-world operational efficiency of hydrogen vehicles and can be used to assess their role in sustainable transport. The study has practical significance in the context of the growing interest in hydrogen technologies and policies for the decarbonization of the transport sector.