In general, this disclosure describes techniques for alerting a user of a mobile communications device of an event using a radio frequency transmitter. The techniques may include determining that an event has occurred. The event may relate to an incoming communication received by the mobile communications device. The techniques also may include determining that an approximate speed of the mobile communications device exceeds a defined threshold speed. The techniques further may include transmitting, using a radio frequency transmitter, an audible alert that provides notification of the event in response to the mobile communications device determining that the approximate speed exceeds the predefined threshold speed.