The flight crew of the business jet was taxiing from the ramp to the runway at night after receiving their departure clearance. As they transitioned from the ramp area to the taxiway, they were crossing a non-licensed vehicle roadway (NLVR). A vehicle traveling along the NLVR collided with the nose of the airplane, substantially damaging the forward portion of the fuselage. The driver of the vehicle stated that she was aware of the signage requiring vehicles to yield to aircraft, and that when she didn’t see an aircraft as she approached the intersection, she continued to drive. She further described that it was dark and raining, but not foggy, and that it was difficult to see. She did not realize that the vehicle had struck the airplane until after the collision, and when she looked back after coming to a stop, she saw the airplane and its illuminated wingtip lights. She further stated that she had not anticipated encountering an airplane at that time of the morning, had become complacent, and that she should have been more observant.