Patent US 5,963,148

An image of a road area ahead of a vehicle is formed based on road data read from a navigation system, or based on an image shot by a camera means such as a video camera. A temperature profile ahead of the vehicle detected by a temperature detecting means such as an infrared camera is superposed on the image of the road area. As a result, if a low-temperature zone is detected on the road area, it is determined that there is snow or ice existing on the road area, or if a high-temperature zone is detected, it is determined that there is a person or animal existing on the road area, thereby informing a driver by an alarm means or a display means to avoid such an obstruction or hazard. Thus, it is possible to perceive snow, ice, a person and an animal existing on a road ahead of the vehicle without relying on a driver's visual judgment, and to give an alarm so that the driver may timely take an appropriate countermeasure to avoid the obstruction or hazardous situation.