When it comes to seat and head restraints in minivans, Fords are the only models to earn the top rating, while most restraints provide inadequate protection against neck injuries, the most common injury in automotive accidents. This claim is made by the Insurance Institute for Highway Safety, based on a study that focused on rear-end crashes and is based on recent evaluations.

Seat/head restraint combinations in the Ford Freestar and its twin Mercury Monterey earn good overall ratings. Those in some Dodge Grand Caravan/Chrysler Town & Country models are rated acceptable. However, the seat/head restraints in most current minivan models are marginal or poor, indicating they wouldn't provide adequate protection from whiplash injuries for many people in rear-end collisions.

The ratings are for seat/head restraint designs available in 14 current minivan models. 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. Seats with good or acceptable restraint geometry then are tested dynamically using a dummy that measures forces on the neck. 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 cannot be positioned to protect many people.

Among the seat/head restraints that were tested dynamically, those in the Honda Odyssey are rated marginal overall. All seats in the Chevrolet Uplander (also sold as Buick Terazza, Pontiac Montana SV6, and Saturn Relay) and some in the Grand Caravan/Town & Country and Toyota Sienna are rated poor. All of these seat/head restraint combinations earn overall ratings based on both geometry and dynamic test results.

"Automakers are improving the geometry of their head restraints, compared with the last time we evaluated them," says Institute chief operating officer Adrian Lund. "Still, in this group of minivans the Fords are the only models with good dynamic performance for all of their seat designs. Many of the seat/head restraints we evaluated didn't even get to the testing stage because of marginal or poor geometry. These cannot begin to protect most people in rear-end crashes."

"It's disappointing that so many minivan seats are rated poor for rear impact protection," Lund says. "Drivers of minivans spend a lot of time on urban and suburban roads where rear-end collisions are common in stop-and-go traffic. Moms often are behind the wheel, and women are more vulnerable to whiplash injuries so they especially need good seats and head restraints."

Neck injuries are the most common kind reported in automobile crashes and are most likely to occur in rear impacts. Whiplash is the most serious injury reported in about 2 million insurance claims each year, which cost at least $8.5 billion. Such injuries aren't life threatening, but they can be painful and debilitating.

"The key to reducing neck injury risk is to keep the head and torso moving together," Lund explains. A head restraint should extend at least as high as the top of the ears of the tallest expected occupant. A restraint also should be positioned close to the back of an occupant's head so it can contact the head and support it early in a rear-end crash.