Abstract: An on-vehicle computer includes a hardware timer. The hardware timer is started when a vehicle accessory switch changes to its OFF position. A suspending request is transmitted from a BIOS to an application program and a BIOS timer is started when the vehicle accessory switch changes to its OFF position. A suspending permission answer is returned from the application program to the BIOS and an application program timer is started in response to the suspending request. A first turn-OFF command is generated when an elapsed time measured by the application program timer reaches a first predetermined time interval (T2). The BIOS is enabled to generate a suspending command in response to the suspending permission answer. A second turn-OFF command is generated in cases where the suspending permission answer continuously fails to be returned to the BIOS until an elapsed time measured by the BIOS timer reaches a second predetermined time interval (T1).

Abstract: In an apparatus for measuring the dynamic state of traffic, a video camera unit picks up images of traffic on the road. The picture information is temporarily stored in memory units, and then processed by an image processing unit. The image processing unit controls the rate for updating background data determines whether it is daytime, dusk or night, and controls a threshold value for processing images. Further, the updating of the background data is made accurate and the extraction or identification of running vehicles is facilitated by employing a background differential system and a frame differential system. The output is transferred to a CPU to be utilized as a source of traffic information or for scheduling travelling time.