JP2809063B

PURPOSE:To improve reliability of a system in an alarm device which generates alarming if a distance to a surrounding object such as a preceding vehicle becomes less than an allowable inter-vehicle distance. CONSTITUTION:The data from a distance measuring sensor 10 which detects a relative distance to a surrounding object and a vehicle speed sensor 12 which detects its vehicle speed are supplied to an electronic control unit ECU16. The ECU 16 compares an allowable distance with a distance to a detected object (including the preceding vehicle), and if it is less than the allowable distance, an alarm signal is outputted to an alarm device 14 to give alarming to a driver. Operating signals from an acceleration/deceleration mechanism 18 such as a throttle and a brake are supplied to the ECU 16 to compute the time which a driver needs for danger clearing operation and its frequency by detecting operation of a throttle which responds to alarming or operation of a brake and adjust alarming sound volume and allowable distance according to the time and frequency.