Between 20 to 25% of the potential range of an electric vehicle is lost as a psychological safety buffer, according to a study by a doctoral candidate at Technische Universität Chemnitz in Germany. The results of the study, which also suggested that assistance systems could reduce the size of that buffer, were based on more than 400,000 km (249,000 miles) of user experience gathered in the research project “MINI E Berlin powered by Vattenfall”.