The safety score is calculated from a dynamic model of the vehicle and GPS variables sampled at 1Hz (one point per second). Data from your smartphone's accelerometer and gyrometer are not taken into account when calculating the safety score.
Indeed, these sensors are more sensitive and can measure events that are not related to driving behavior (falling of the phone in the vehicle, handling of the phone by a passenger, etc.).
That is why we have decided not to use this information. On the other hand, we have developed a distraction score that is independent and aims to measure the driver's interactions with his smartphone.