Crash detection on mobile device

An apparatus comprising:

• at least one motion sensor;
• at least one processor;
• memory storing instructions that when executed by the at least one processor, cause the at least one processor to perform operations comprising:
• detecting a crash event based at least in part on sensor data from the at least one motion sensor;
• extracting multimodal features from sensor data generated by multiple sensing modalities of the apparatus;
• computing a plurality of crash decisions based on a plurality of machine learning models applied to the multimodal features;
• and
• inferring that a severe vehicle crash has occurred involving the apparatus based on the plurality of crash decisions and a severity model;
• responsive to a severe crash being determined, presenting a notification on a screen of the apparatus requesting a response from a user of the apparatus;
• determining whether the apparatus is stationary for a predetermined period of time;
• responsive to the apparatus being stationary for the predetermined period of time,
• starting a timer or counter;
• determining that the timer or counter meets a threshold time or count, respectively;
• and
• escalating the notification.