2015 Toyota Prius C Rated IIHS Top Safety Pick after Structural Fix "After a fix to the front end structure and curtain airbags, the 2015 Toyota Prius C improves its performance in the Insurance Institute for Highway Safety’s small-overlap crash test, meaning that the hybrid hatch is now rated as a Top Safety Pick. The rating applies to all 2015 Prius C models manufactured after May 2015. "The Prius C previously received a “Poor” rating on the small-overlap test, but Toyota made structural fortifications to the front end and passenger compartment of the vehicle, and also lengthened the side curtain airbags. This helped the Prius C up its rating to “Acceptable,” as the updated model was able to better maintain the driver’s space in the small-overlap test, and reduce intrusion into the passenger compartment."
So unless Toyota makes more adjustments for 2016, the Prius c will only be a Top Safety Pick for half a year.