here's kris van cleave. >> reporter: stricter criteria for passenger protection in this crash test, and poor-performing headlights caused the number of vehicles earning the insurance institute of highway safety's top safety ranking to plummet. >> the reason we do these tests is to show automakers where they need to improve their vehicle designs. >> reporter: i.i.h.s. president adrian lund. >> we want doors to light up the road at night, because we have a lot of-- particularly the more serious crashes that occur at night. and part of that reason is because headlights haven't been very good. >> reporter: just these 15 vehicles were given the top safety pick-plus rating, that's down from 16 last year. no minivans, pickups, or minicars made the list. during the designation, vehicles have to have good ratings in crash tests and roof strength, as well as high marks for crash- avoidance technology. that's in addition to the better headlight standards and additional passenger crash protection. headlight performance also