Active safety systems or "driver assists" use cameras and sensors to warn a driver of impending danger. The systems can even take action, such as steering the car or applying the brakes, to avoid a collision. Some driver assists still are found on high-end vehicles, but others have trickled down to less expensive cars. Lane-departure warning technology can sense when a driver has inadvertently drifted out of a lane and flash a visual alert and sound an alarm. Lane-departure intervention (also called lane-keeping assist) goes a step further, automatically steering a car back into its lane when a driver doesn't heed the warning. The systems can be found, for example, in the current Chevrolet Volt, Ford Fusion and Honda Accord.