In this paper we present the approach to use smartphones as a multi sensor platform in a field operational test respectively a naturalistic driving study. Modern smartphones offer the sensor capability to detect speed and position as well as the accelerations that are experienced by the phone. With our approach those sensors can be used to measure the mobility with a car or other vehicles. First we will explain the advantage of smartphones over dedicated data loggers for certain purposes. Then we describe the measurement system and the application that has been built-up for that purpose and afterwards we will discuss the calibration process for the acceleration data in the post- processing to fit the car’s coordinate system. Finally we show results from a measurement campaign to validate the data recorded with several smartphones in comparison to results recorded with a highly accurate inertial measurement platform.