Once again, Volvo has proven itself as a leader in occupant protection with an impressive four IIHS Top Safety Picks. Congratulations to the Volvo S80, C30, XC60, and XC90. To determine crashworthiness - how well a vehicle protects its occupants in a crash - the Institute rates vehicles as good, acceptable, marginal, or poor based on performance in high-speed front and side crash tests, a rollover test, plus evaluations of seat/head restraints for protection against neck injuries in rear impacts. To earn Top Safety Pick for 2010 a vehicle must have good ratings in all four Institute tests and offer electronic stability control.
Side evaluations are based on performance in a crash test in which the side of a vehicle is struck by a barrier moving at 31 mph. The barrier represents the front end of a pickup or SUV. Ratings reflect injury measures recorded on two SID-IIs dummies representing a fifth-percentile woman, assessment of head protection countermeasures, and the vehicle's structural performance during the impact.
Rear crash protection is rated according to a two-step procedure. Starting points for the ratings are measurements of head restraint geometry - the height of a restraint and its horizontal distance behind the back of the head of an average-size man. This test simulates a collision in which a stationary vehicle is struck in the rear at 20 mph. Seats without good or acceptable geometry are rated poor overall because they can't be positioned to protect many people.
In the roof strength test, a metal plate is pushed against one side of a roof at a constant speed. To earn a good rating for rollover protection, the roof must obtain a suitable strength-to-weight ratio by withstand a force four times the vehicle's weight before reaching five inches of crush. The minimum required strength-to-weight ratio is 3.25. A marginal rating value is 2.5, and any lower ratings are categorized as poor.