Abstract: A system for electronically controlling vehicle operation vehicle and a method therefor applied to a cruise control, which utilizes fuzzy logic or approximate reasoning in determining a control output. Namely, vehicle operating conditions are assigned on a scale called a universe of discourse having degrees of 0 to 1.0 called membership functions or degrees. The detected conditions are identified on the universe and are then defined by fuzzy labels which are in turn used for retrieving control rules expressed in similar labels. Pertinent control rules are composed in fuzzy relation so as to obtain a scaled or universe value which is then converted into a real numerical value. The value is finally sent to a pulse motor control device which opens or closes a throttle valve in order to maintain the vehicle at a predetermined cruising speed.