A method of alerting a vehicle's driver. The method comprises receiving an azimuth value indicating a gazing direction of a head of the driver from a primary device placed on the driver, receiving a vehicle bearing value indicating a vehicle moving direction of the vehicle driven by the driver, calculating an angular difference between the azimuth value and the vehicle bearing value, generating an alert when the angular difference deviates from an angular threshold, and automatically presenting the alert to the driver in response to the angular difference.
