2013 Nissan LEAF Scores Lower In Safety Than The Previous Year's Model
National Highway Traffic Safety Administration (NHTSA) has given the new US-made 2013 Nissan LEAF only four stars, despite the previous generation (2011-2012) receiving five.
2011-2013 Nissan LEAF NHSTA Safety Ratings
Looking at the SafeCar webisite, the reason seems to be from weaker protection of female passengers in front and side crash (only 3 stars in these cases) that wasn't offset enough by better driver protection (5 stars).
2013 Nissan LEAF Cross Section
It is hard to say what caused the lower safety rating specifically because new LEAF which is produced at Smyrna, TN isn't much different from the original 2011 and 2012 models made in Oppama, Japan.
Potentialy it could be affected by the 2013's weight reduction and drivetrain integration under the hood.
Earlier this week, the 2013 LEAF still collected the "Top Safety Pick" award from the Insurance Institute for Highway Safety (IIHS).
Video of the 2013 Nissan NHSTA LEAF crash tests: