  Smartphone usage while driving is unanimously considered to be a really
dangerous habit due to strong correlation with road accidents. In this paper,
the problem of detecting whether the driver is using the phone during a trip is
addressed. To do this, high-frequency data from the triaxial inertial
measurement unit (IMU) integrated in almost all modern phone is processed
without relying on external inputs so as to provide a self-contained approach.
By resorting to a frequency-domain analysis, it is possible to extract from the
raw signals the useful information needed to detect when the driver is using
the phone, without being affected by the effects that vehicle motion has on the
same signals. The selected features are used to train a Support Vector Machine
(SVM) algorithm. The performance of the proposed approach are analyzed and
tested on experimental data collected during mixed naturalistic driving
scenarios, proving the effectiveness of the proposed approach.
