1. A system for providing warnings of hazards to a user, comprising: a first sensor that detects at least one of a region and an object in an environment of the user; a second sensor that detects activities of the user, wherein the first and second sensors are wearable by the user; at least one wearable acoustic transducer arranged relative to an ear of the user; and a processor programmed to: identify a hazard to the user based on at least one of a detected region and a detected object; determine whether a detected activity of the user indicates awareness by the user of the identified hazard; and upon determining that the detected activity does not indicate awareness of the identified hazard, output to the at least one acoustic transducer an audio warning for the identified hazard.