The system can be turned off at different levels, you can have it fully on with a warning beep and steering assist (which steers you back easily and is not jerky whatsoever), you can turn the steering assistance off and just have it beep at you or you can completely have it turned off. You can also set the sensitivity/distance for the system to alert you when you veer near the lane marker. The system uses the camera to monitor lanes when available. The system does not work when there are poorly painted lanes or when weather is inclement such as a snow storm. The steer system works well for corrections but is not as robust as lets say the Tesla Model S that will drive its self to a certain extent. I only use the system on long highway trips as it personally annoys me around town where lane changes occur at a quicker pace.