A computer implemented method comprising: receiving signals from one or more detectors housed in a mobile device while the mobile device is on a trip, the detectors comprising at least an accelerometer and a gyroscope, using the received signals from the detectors to identify one or more physical states of the mobile device during the trip, the physical states comprising speed of motion of the mobile device along a trajectory of the trip, and operational state of the mobile device, based on the identified physical states, generating discrete events separated in time, at least one of the discrete events comprising the mobile device being picked up, rotated, held by, tapped on, or facing in the direction of a driver of a vehicle, and determining a distraction episode that spans two or more of the discrete events during the trip, the determining of the distraction episode comprising determining a possible distraction episode and determining that the possible distraction episode comprises a true distraction episode, wherein determining that the possible distraction episode comprises a true distraction episode comprises: determining that each of three conditions hold true, the three conditions being mobile device movement, user interactions with the mobile device, and vehicle speed during the episode exceeding a predetermined threshold, determining that a start of the possible distraction episode occurs when a) one of two conditions holds true, the two conditions being mobile device movement and user interactions with the mobile device, and b) both of the two conditions simultaneously hold true at a time within a threshold period of time after the one of the two conditions holds true, determining that an end of the possible distraction episode occurs when i) a context of the mobile device indicates no further distraction, ii) no further movement of the mobile device is detected, and iii) a refractory period has elapsed during which neither i) nor ii) holds true, and determining that a time period spanned by the possible distraction episode is longer than a predetermined length. receiving signals from one or more detectors housed in a mobile device while the mobile device is on a trip, the detectors comprising at least an accelerometer and a gyroscope, using the received signals from the detectors to identify one or more physical states of the mobile device during the trip, the physical states comprising speed of motion of the mobile device along a trajectory of the trip, and operational state of the mobile device, based on the identified physical states, generating discrete events separated in time, at least one of the discrete events comprising the mobile device being picked up, rotated, held by, tapped on, or facing in the direction of a driver of a vehicle, and determining a distraction episode that spans two or more of the discrete events during the trip, the determining of the distraction episode comprising determining a possible distraction episode and determining that the possible distraction episode comprises a true distraction episode, wherein determining that the possible distraction episode comprises a true distraction episode comprises: determining that each of three conditions hold true, the three conditions being mobile device movement, user interactions with the mobile device, and vehicle speed during the episode exceeding a predetermined threshold, determining that a start of the possible distraction episode occurs when a) one of two conditions holds true, the two conditions being mobile device movement and user interactions with the mobile device, and b) both of the two conditions simultaneously hold true at a time within a threshold period of time after the one of the two conditions holds true, determining that an end of the possible distraction episode occurs when i) a context of the mobile device indicates no further distraction, ii) no further movement of the mobile device is detected, and iii) a refractory period has elapsed during which neither i) nor ii) holds true, and determining that a time period spanned by the possible distraction episode is longer than a predetermined length. determining that each of three conditions hold true, the three conditions being mobile device movement, user interactions with the mobile device, and vehicle speed during the episode exceeding a predetermined threshold, determining that a start of the possible distraction episode occurs when a) one of two conditions holds true, the two conditions being mobile device movement and user interactions with the mobile device, and b) both of the two conditions simultaneously hold true at a time within a threshold period of time after the one of the two conditions holds true, determining that an end of the possible distraction episode occurs when i) a context of the mobile device indicates no further distraction, ii) no further movement of the mobile device is detected, and iii) a refractory period has elapsed during which neither i) nor ii) holds true, and determining that a time period spanned by the possible distraction episode is longer than a predetermined length.