Methods, systems, and apparatus, including computer programs encoded on computer storage media for driver detection are described. One example method includes monitoring data provided by an accelerometer associated with a client device. It is determined whether the data indicates a particular event associated with a vehicle. In response to determining that the data indicates the particular event associated with the vehicle, one or more micro-activities associated with the vehicle are determined based on data from at least one of the accelerometer and one or more other sensors associated with the client device. Results from each of the one or more micro-activities are provided to a trained model associated with the client device. In response to providing the results to the trained model, one or more vehicular events in a time sequence are identified based on the one or more micro-activities associated with the vehicle.