Head restraints in several sport utility vehicles and pickups poorly protected test dummies from neck injuries in a simulated rear crash at 20 mph, the insurance industry reported Sunday.
Only six of the 44 SUVs and none of the 15 pickups tested earned top scores.
Automakers said their vehicles were safe and met federal standards. Some contended that variations in the crash could produce different ratings for the same vehicle.
"Manufacturer advertising often emphasizes the rugged image of SUVs and pickups," said Adrian Lund, president of the Insurance Institute for Highway Safety, an industry-funded group. "However, the institute's evaluations show seats and head restraints in many models wouldn't do a good job of protecting most people in typical rear impacts," Lund said.
SUVs from the 2006 model year rating poorly were the Acura MDX; BMW X3 and X5; Buick Rainier; Chevrolet TrailBlazer; GMC Envoy; Isuzu Ascender; Chrysler Pacifica; Ford Explorer; Mercury Mountaineer; Honda CR-V; Honda Element; Hyundai Santa Fe; Hyundai Tucson; Jeep Liberty; Kia Sorento; Kia Sportage; Lexus GX 470; Lexus RX 330; Nissan Xterra; Cadillac SRX; Jeep Wrangler; Mitsubishi Endeavor; Mitsubishi Montero; Suzuki Grand Vitara XL-7; Toyota 4Runner; and certain models of the Toyota Highlander.
The six 2006 SUVs receiving the top score were the Ford Freestyle, Honda Pilot, Jeep Grand Cherokee, Land Rover LR3, Subaru Forester and the Volvo XC90.
Scoring the second-highest rating of acceptable was the Ford Escape, Mazda Tribute and Mercury Mariner.
The remaining SUVs were considered marginal, the second-to-worst ranking: Buick Rendezvous; Chevrolet Equinox; Infiniti FX; Mercedes M Class; Mitsubishi Outlander; Nissan Pathfinder; Pontiac Torrent; Saturn Vue; and certain models of the Toyota Highlander.
Among pickups, the institute gave poor ratings to the Chevrolet Silverado 1500; GMC Sierra 1500; Dodge Ram 1500; Ford Ranger; Mazda B Series; Nissan Frontier; and versions of the Ford F-150 and Dodge Dakota.
Three models were deemed acceptable: Nissan Titan and versions of the Dodge Dakota and Toyota Tundra. The rest were marginal: the Chevrolet Colorado; GMC Canyon; Isuzu i280 and i350; Toyota Tacoma; and certain versions of the Toyota Tundra and Ford F-150.