Acura RDX and BMW 3 series earn IIHS Top Safety Pick award

The 2013 RDX and 2012 3 series, both redesigned models, earn the Institute's top award for affording occupants good protection in front, side, rollover and rear crashes.

The RDX, a midsize luxury SUV, and the 3 series, a midsize luxury car, earn the award with improved roof strength for protection in rollover crashes. Top Safety Pick only applies to the redesigned 4-door version of the 3 series.

To measure roof strength, a metal plate is pushed against one corner of a vehicle's roof at a constant speed. The maximum force sustained by the roof before 5 inches of crush is compared to the vehicle's weight to find the strength-to-weight ratio. This is a good assessment of occupant protection in rollovers.

The 2007-12 RDX was rated marginal for roof strength. The 2006-11 3 series was rated acceptable.