The aim of this study is to develop a methodology for validating driving simulators in terms of simulator usability. The methodology was used to validate a truck simulator designed for training truck drivers about economic fuel consumption. The participants were eight truck drivers. Interview and observation methods were used to gather data. The results of the study showed that drivers did not have difficulty to recognize the parts of the driving simulator. Also, they stated that driving the simulator was easy. However, they said that they had some difficulties to use some systems of the simulator.