When it's available sometime next year with an estimated price tag of around $200, the advanced ICEdot monitor will attach to any bike helmet and use motion and impact sensors to intelligently determine if the wearer has been involved in an accident. Using the new Bluetooth low-energy profile it maintains a constant connection to a smartphone app so that when an accident occurs, it can automatically alert the rider's emergency contacts with the time and GPS coordinates of the incident.
And to avoid false positives, since there's always the chance a dropped helmet could be misconstrued as a nasty tumble, the app initiates an emergency countdown which can be manually aborted in the event nothing actually happened. If you ride in a big city where the 'mind your own business' mentality prevails, this could be the perfect accessory if no one comes to your rescue after a crash. More here.