Some cars sound warning beeps when your car crosses a solid or dotted lane marking, then silences itself once it's away from the lane edge. (extremetech.com)
Lane Departure Warning beeps at the driver when the vehicle drifts out of its lane without using a turn signal, whereas Lane Departure Prevention takes things a step further by bias braking to pull the vehicle back into its lane. (cnet.com)
This doesn't prove intrusive enough to encourage me to turn off the system — and at least there's no constant barrage of warning beeps when it intervenes. (driving.ca)