Vehicle cruising control device

A vehicle cruising control device comprising:

• detecting means for detecting the current speed of a first vehicle;
• measuring means for measuring current inter-vehicle distance between said first vehicle and a second advance vehicle;
• calculating means for calculating the relative speed between the first vehicle and the second advance vehicle and for calculating a degree of danger based on said distance and said relative speed;
• inter-vehicle distance control means for maintaining the inter-vehicle distance between the first vehicle and the second advance vehicle at a predetermined distance based on an output from said measuring means when said degree of danger determined by said calculating means exceeds a predetermined value;
• constant speed control means for maintaining the speed of the first vehicle at a selected speed based on an output from said detecting means when said degree of danger is less than said predetermined value;
• control means for operating one of said inter-vehicle distance control means and said constant speed control means exclusive of the other based on said degree of danger;
• and
• switching means for selectively activating either one of said constant speed control means and said inter-vehicle distance control means regardless of said degree of danger.