In frontal offset crash tests conducted recently by the Insurance Institute for Highway Safety (IIHS), eight new or redesigned midsize SUVs earned ratings of good, and one is acceptable.Three luxury models (Lexus RX 330, Infiniti FX, and Cadillac SRX) earned good ratings overall and the added designation of "best pick." Five other SUVs (Toyota 4Runner, Nissan Murano, Chrysler Pacifica, Honda Pilot, and Mitsubishi Endeavor) also earned good ratings. The Kia Sorento is rated acceptable. Vehicle ratings reflect performance in 40 mph frontal offset crash tests into a deformable barrier.Based on the results, the IIHS evaluates the crashworthiness of passenger vehicles, assigning each vehicle a rating from good to poor overall. If a vehicle earns a good rating, it means that in a real-world crash of similar severity a belted driver would be likely to walk away without serious injuries. "These results demonstrate the effectiveness of the IIHS's frontal crash test program in bringing about improvements in vehicle design," says Adrian Lund, the IIHS's chief operating officer. "When the IIHS first tested midsize SUVs in 1996, none was rated good. Now 16 current midsize SUV designs are rated good." But Lund notes that "Seven still are rated marginal or poor."IIHS and government crash tests complement each other: The IIHS's crashworthiness evaluations are based on results of frontal offset crash tests at 40 mph. Each vehicle's overall evaluation is based on three aspects of performance — measurements of occupant compartment intrusion, injury measures from a Hybrid III dummy positioned in the driver seat, and analysis of slow-motion film to assess how well the restraint system controlled dummy movement during the test.The federal government has been testing new passenger vehicles in 35 mph full-front crash tests since 1978. This New Car Assessment Program has been a major contributor to crashworthiness improvements — in particular, improved restraint systems in new passenger vehicles. The IIHS's offset tests, conducted since 1995, involve 40 percent of a vehicle's front end hitting a deformable barrier at 40 mph. This test complements the federal test involving the full width of the front end hitting a rigid barrier. Both tests are contributing to improvements in crashworthiness — in particular improved crumple zones and safety cages.