1. A method of controlling the down-switching of a multibeam pattern headlamp system in a vehicle when opposing vehicles approach within the corresponding beam pattern, comprising the steps of: providing headlamps on said vehicle for projecting a plurality of predetermined high intensity patterns directed outwardly from the vehicle in overlapping areas; providing a source of electrical energy for energizing the headlamps; providing a switching means that is controllable to connect said source of electrical energy to selected headlamps; providing a first sensor for sensing the presence of headlamp radiation from oncoming vehicle headlamps over a wide range including said overlapping areas of said beam patterns and indicating said presence when said oncoming radiation is sensed as being above a predetermined threshold; providing a second sensor for sensing the presence of headlamp radiation from oncoming vehicle headlamps within a limited area of said overlapping beam patterns corresponding to one of the beam patterns and indicating said presence when the intensity of said oncoming radiation is sensed as being above a predetermined threshold; and controlling said switching means in response to the indications from said first and second sensors in order to down-switch said headlamp beam patterns by disconnecting said source of electrical energy from appropriate headlamps and restoring said connections when said first and second sensors cease to provide said indications.