With more vehicles being designed with third-row seats, some consumers are concerned with the safety implications of seating people—usually children—closer to the vehicle's rear, where they could be more vulnerable during a rear crash. Because of limited data, there is no clear-cut picture regarding third-row-seat safety.
Reliable accident data are thin, partly because third rows are often unoccupied. Also, without evidence of a problem, automakers are not required to conduct rear-crash tests with dummies.
Although third-row passengers are closer to the impact point in rear collisions, they are farther from that point in front collisions, which are more common and usually more harmful. The biggest danger to third-row passengers in a rear-ender is posed when the passenger is an adult and sitting in a seat with an inadequate head restraint and no three-point seat belt. A properly installed child seat provides more protection.
Other considerations: Third-row seats are usually found in larger, heavier vehicles, which generally provide better crash protection. The rate of serious, accident-related injuries for children in minivans is only half that of those in passenger cars, with SUVs a close second.
Still, there's a growing trend for smaller vehicles to offer a third row, including small SUVs like the Toyota RAV4, or hatchbacks such as the Mazda5 and Kia Rondo. Those third-row seats tend to be very close to the tailgate, which means there's little crush space available in the event of a severe rear-end impact. Again, though, the relative rarity of high-speed rear-enders and the low occupancy rate of third-row seats means that there is precious little data on which to make a safety judgment.
Although there is no evidence that the third row is less safe overall, you should take prudent measures. Most important: Properly restrain all passengers. When possible, seat children in the second row. The center position, farthest from a side-impact point, is best as long as it's equipped with a three-point safety belt and adequate head restraint. Young children should not be in the front passenger seat.
When buying a vehicle with three rows, look for one that has side-curtain air bags that reach all the way back there. Children too big for child seats need lap-and-shoulder belts and head restraints that reach at least as high as the top of their ears. Check the owner's manual for occupant weight limits or other restrictions.