Abstract: The present invention corresponds to a weigh-in-motion system for motor vehicles based on flexible, fiber-optic sensors. The field of application of the patent object is the measurement of dynamic physical events that are caused directly or indirectly by the passage of a motor vehicle over the sensors. This system consists of 5 blocks: an information processing and display equipment (5) is connected to an optical emission and detection equipment (2), one or more presence sensors (3), a temperature sensor (4), and one or more weight sensors (1). It has advantages over other technologies, such as: simplified manufacture and compact size, sensors immune to electromagnetic interference, long service life, and the possibility of being installed on different types of pavement.