If the system determines that the vehicle may deviate from its lane, the lane departure warning (beep sound, rumble sound*1, or steering wheel vibration) is activated and the direction in which the system determines that the vehicle may deviate is indicated in the multi-information display and the active driving display.
If the system determines that the vehicle may deviate from its lane, the color of the lane line on the side being detected by the system changes from white to amber, and flashes.


NOTE
*1 A rumble strip is a series of grooves in the road pavement surface positioned at specific intervals, and when the vehicle passes over it a vibration and rumble sound is produced which alerts the driver that the vehicle is departing from the lane. The rumble sound is a reproduction of the sound which occurs when a vehicle passes over a rumble strip.

System Canceling
Smart City Brake Support (SCBS)Mazda 6 Owners Manual: No. 2 all on-board diagnostic functions inoperative
When performing an asterisked (*) troubleshooting inspection, shake the
wiring harness and connectors while doing the inspection to discover whether
poor contact points are the cause of any intermittent malfunctions. If there
is a problem, check to make sure connectors, terminals and wir ...
Mazda 6 Owners Manual: Scheduled Maintenance (U.S.A., Canada, and Puerto Rico)
Follow Schedule 1 if the vehicle is operated mainly where none of the following
conditions (severe driving conditions) apply.
Repeated short-distance driving
Driving in dusty conditions
Driving with extended use of brakes
Driving in areas where salt or other corrosive materials are used
...