Increasing the role of logistics in business area due to globalization in production and consumption market, and competition pressure to cut costs and offer on time, reliable and affordable services, make transportation role more fundamental in business strategy. In this respect, consideration to have more efficient transportation and higher utilization of transport capacity leads to focusing on filling rate measurement as an efficiency measurement system in decision making process. The purpose of this study is to investigate different ways of measuring fill rate in road freight transport and evaluating them. To achieve this purpose, previous studies on role of filling rate in efficiency measurement systems, factors affecting filling rate, and different methods for its calculation have been studied. To get more practical data interviews have been performed with leading companies in logistics industry as well as scholar specialists in academic area. The outcome of the study is an analysis of fill rate perception and application in transportation industry, comparison and evaluation of existing methods of measuring fill rate, and possible ways to improve it.