ARLINGTON, VA — Five minivan models have earned the 2011 Top Safety Pick award from the Insurance Institute for Highway Safety. The 2012 Chrysler Town & Country, Dodge Grand Caravan and Volkswagen Routan — which all share a common structure — join the Honda Odyssey and Toyota Sienna in the Top Safety Pick ranks following new evaluations for rollover protection.

"To qualify for the designation, vehicles must have the highest rating of "good” for frontal, side, rollover and rear crash protection and must have electronic stability control (ESC).

IIHS said the winners stood out from competitors because of superior protection in rollover crashes.

Rollover protection depends on roof strength, which is measured by pushing a metal plate against one corner of a vehicle's roof at a constant speed. To earn a "good" rating, the roof must withstand a force equal to four times the vehicle's weight before it caves in 5 inches. Put another way, it must have a strength-to-weight ratio of at least four.

For more details about the minivan test results, click here.