
An available Lane Keep Assist [1] system applies steering torque to help the vehicle stay in the center of the lane (provided, of course, you're on a road with clearly marked lines).
To help keep you from drifting out of your lane when cruise control is in operation, an available Lane Departure Warning [2] system gives an audible warning. After this warning, it takes corrective steering action to help keep you in your lane. When cruise control is not engaged, the system sounds a warning if you drift out of your lane.