Premium Performance or Standard Octane Rating? A Multi-Year Empirical Statistical Analysis of Fuel Consumption Efficiency and Major Brand Refueling Locations

This multi-year time series research investigates the main drivers of automotive fuel efficiency, a heavily debated topic among motorists, but often obscured and clouded with scientifically unverified personal claims and/or regional biases. While most academic papers frequently question actual fuel saving claims and/or the cost-benefit ratio of high-octane fuels, little to no other studies provide a more extended dataset, with cross-border empirical data necessary to back up these technical claims in real-world conditions. This research utilizes an extensive dataset spanning over 5 years (2021–2025) and over 180,000 kilometers of transit across 6 European countries. Welch’s t-test and both single and two-factor ANOVA were used within the study to address two main issues: the quantifiable efficiency gain of premium fuel (98+ RON) over the standard 95 RON petrol and how some fuel brands compare to the geographic location of refueling. The results confirm that premium fuels source a statistically significant efficiency gain of 4.72% (p = 0.016), resulting in a drop in average consumption of 0.345 L/100 km. Furthermore, while the analysis shows that major brands like Shell, OMV and/or MOL are essentially performing at the same technical level, the country of refueling proved to be a key determinant of variance (p = 0.031). This highlights that regional variables, such as road infrastructure, air quality and topography, have a more substantial influence on performance than the specific additives and fuel formulas used by different brands. The paper contributes to the field by shifting the focus from brand competition to the importance of where a driver refuels and differences in fuel chemistry. These findings offer a practical benchmark and new insights to high-mileage drivers, providing a reliable and solid statistical foundation for improving fuel savings and other operational costs through smarter fuel selection.