By Angela Stringfellow on July 25, 2011 in
You know those metal U-shaped anchors nestled into your car's back seat? How about the metal rings found just behind the back seat's headrest? Those are part of the LATCH (Lower Anchors and Tethers for Children) system, a standardized child restraint anchorage system that allows child safety seats to be installed without using the vehicle's seat belt system. Cars are required to have upper tether anchors in at least two rear passenger seats. These rings are affixed to the top of an infant car seat to provide a more secure attachment and reduce the risk of injury in an accident. And while most parents adhere to the guidelines from their car seat manufacturer in terms of weight and age limits and proper usage, vehicles' weight limits for the LATCH system can differ from what car seat manufacturers recommend.
CarSeatBlog.com says that in the 2011 edition of the LATCH manual, Honda and its luxury counterpart Acura report a 40-pound weight limit on both lower anchors and upper tether anchors in their vehicles. A stated weight limit refers to the child's weight (not the weight of the child plus the weight of the car seat). This number indicates that the tether anchors have been found to be reliable in safety testing when used with children weighing 40 pounds or less in a forward-facing car seat, but the anchors may fail when used with a child weighing more than 40 pounds.
Ferrari and Mercedes-Benz also state 40 pounds as a weight limit for both upper and lower anchors, while other manufacturers either state higher weight limits or defer to the car seat manufacturer's instructions. Most child restraint systems are rated for 65 to 80 pounds, leaving a large gap between the ability to use the upper tethers and the overall lifespan of the car seat.
Tether Anchors: To Use or Not to Use?
This discrepancy brings up an important question: After your child reaches 40 pounds (if you drive a Honda, Acura, Ferrari or Benz), should you discontinue the use of the tethers, and if so, what's the alternative? CarSeatLady.com suggests that lower anchors be used up to the 40-pound limit and then swapped out for the vehicle's safety belt. Because it's the lower anchors that bear the brunt of the force in a crash, adhering to these guidelines is especially important.
But when it comes to upper tether anchors, there is no accepted alternative for securing the top portion of an infant car seat to the vehicle's seat. Further complicating matters, most child restraint systems sold for use with children weighing 40 pounds or more require the use of the upper tethers. The general consensus among child safety experts is that the risks of not using the upper tethers at all far outweigh the risks of the tethers failing in a crash, so most recommend continuing to use them regardless of the child's weight.
In fact, ConsumerReports.org encounters this issue during a recent round of toddler booster seat testing. Editors point out that several manufacturers, including Graco and Britax, state specifically in the instruction manual that upper tether anchors should always be used if available. Addressing the use-or-not-to-use issue, editors say: "The likelihood of a top tether-anchor failing when anchoring a higher-weight child is unlikely and has not been seen in real-world crashes. And if an anchor were to fail, it would still have provided some benefit in reducing forward movement and absorbing energy from the crash as it deformed." In other words, a tether that fails is better than no tether at all for avoiding head injuries.
Know Your Tether Anchor Weight Limits
We called the National Highway Traffic Safety Administration (NHTSA) for their take on tether anchor weight limits. According to their hotline, their organization does not set weight limits for tether anchors so they defer to the vehicle and car seat manufacturers for guidelines. If your vehicle's manual defers to the car seat manufacturer for weight limits, it's safe to assume that both the upper and lower tethers are appropriate for use throughout the life of the car seat. The NHTSA does recommend that car seats be replaced every six years to assure compliance with the latest safety standards.
For more tips on child safety in the backseat, join us for a #KidsInTheCar Twitter Party on Tuesday, July 26 at 4PM EST.