Mazda 6 Owner's Manual page 328

When Driving
i-ACTIVSENSE
The Lane-keep Assist System (LAS) &
Lane Departure Warning System (LDWS)
goes on stand-by status in the following
cases:
The system cannot detect white (yellow)
lane lines.
The vehicle speed is less than about 60
km/h (37 mph).
The ABS/TCS/DSC is operating.
The DSC is turned off.
(If the DSC is turned off while the
system is operational, a warning beep is
heard and the system goes on standby.)
The vehicle is making a sharp curve.
The driver takes his or her hands off the
steering wheel (not holding the steering
wheel).
The brake pedal is depressed.
4–174
NOTE
(When the timing of the steering
assist is set to "Late")
The Lane-keep Assist System
(LAS) & Lane Departure Warning
System (LDWS) does not operate
until the system detects white
(yellow) lane lines on either the
left or right.
When the system detects a white
(yellow) lane line on one side
only, the system will not operate
the steering wheel operation assist
for the lane line on the side that is
not being detected. The warning
is only for a lane deviation on the
side that is being detected.
(When the timing of the steering
assist is set to "Early")
When the steering assist timing
is set to "Early", the Lane-keep
Assist System (LAS) & Lane
Departure Warning System
(LDWS) does not operate until
the system detects white (yellow)
lane lines on the left and right.
When the system only detects
white (yellow) lane lines on either
the left or right, the system only
operates for a lane deviation on the
side being detected.
The steering wheel operation
assist is performed so that the
vehicle remains near the centre
of the driving lane, however,
depending on conditions such as
the road curvature, road slope and
undulations, and vehicle speed, the
system may not be able to keep
the vehicle near the centre of the
driving lane.