A backup camera (also called a reversing camera or rear-view camera) is a special type of video camera that is produced specifically for the purpose of being attached to the rear of a vehicle to aid in backing up and to alleviate the rear blind spot. It is designed to avoid a backup collision. The area directly behind vehicles has been described as a "killing zone" due to associated accidents. Backup cameras are usually connected to the vehicle head unit display. A common variant is a Surround View system, which assembles a synthetic but positionally accurate top-down view of the vehicle and its adjacencies. Backup cameras have been regulated by law in Canada and the United States since 2018. Backup cameras are increasingly common on new vehicles and beginning in May 2018 they are now required on all new automobiles sold in the United States. Function The design of a backup camera is distinct from other cameras in that the image is horizontally flipped so that the output is a mirror image. This is necessary because the camera and the driver face opposite directions, and without it, the camera's right would be on the driver's left and vice versa. A mirrored image makes the orientation of the display consistent with the physical mirrors installed on the vehicle. A backup camera typically uses a wide-angle or fisheye lens. While such a lens impairs the camera's ability to see faraway objects, it allows the camera to see an uninterrupted horizontal path from one rear corner to the other. The camera is typically pointed at a downward angle to view potential obstacles on the ground. Backup cameras make use of dashboard screens that are also used with GPS navigation systems. Inside the vehicle, the display is typically wired to automatically sense when the transmission is set in reverse, showing the backup view on the dashboard screen while the vehicle is in reverse and/or providing grid guidelines by detecting the parking lot markings to aid the driver. Variations Backup cameras are produced in different varieties depending on the application. Backup cameras can be added as aftermarket additions to vehicles that do not come with factory-fitted systems. They are available in both wired and wireless versions. For large vehicles such as motorhomes, camera systems with built-in servomechanisms allow the driver to remotely pan and tilt the camera. Wireless Backup Cameras come with a wireless camera