Installing a car seat can be daunting. (And it’s especially alarming to learn that most parents do it incorrectly.) It’s a little easier, in theory, if you use the LATCH system. But LATCH isn’t perfect, and there’s a lot to learn about how and when to use it. So we turned to New York City’s Car Seat Lady, Alisa Baer, M.D., to help us understand it all. And wow, did she break it down for us.

StrollerTraffic: Let’s start with the basics. What is LATCH?
Alisa Baer: LATCH stands for Lower Anchors and Tethers for CHildren. It is a way of connecting the car seat to the vehicle that does not use the vehicle’s seat belts.

ST: Is LATCH safer than a seat belt?
AB: NO! Seat belts have always been a very safe and effective way to secure a car seat . . . the problem is that getting a secure installation with a seat belt is often confusing and challenging. LATCH was invented in an attempt to decrease the misuse rate for car seats by giving parents an easier way to secure the child’s car seat to the vehicle. Unfortunately, LATCH did not reduce the misuse rate for car seats.

ST: Got it. Please continue. We want to hear more about lower anchors.
AB: Lower anchor straps can be found on all rear-facing seats, forward-facing seats, and some boosters. The lower anchor straps are typically used instead of the vehicle’s seat belt, except with booster seats where the lower anchor straps secure the booster to the vehicle and the vehicle’s seat belt goes across the child’s body to secure the child. One other exception: the Clek Foonf (a convertible seat) uses rigid lower anchor connectors and the vehicle’s seat belt (and the top tether too), when forward-facing.

ST: And tethers?
AB: Tethers (also called top tethers) are a way of connecting the head of the child’s car seat to the vehicle. It’s a two-part system: there needs to be a tether anchor in the vehicle and a tether strap on the child’s car seat. Tethers are never used by themselves; they are always used in addition to the lower anchors or the vehicle’s seat belt. Tether straps can be found on the top of every forward-facing car seat—and some booster seats. While all convertible seats have tether straps (because convertibles can be used forward facing), only a few allow the tether to be used when the seat is rear-facing.

ST: We understand that lower anchors are an alternate way to connect a car seat to a car. But what’s the role of tethers?
AB: A tether is the most important part of every forward-facing seat. Tethers are tremendously important in decreasing the risk of brain and spinal cord injuries as they decrease how far the child’s head moves forward in a crash by 6 to 8 inches. Tethers spread the stress of the crash onto a larger area of the car seat, rather than concentrating the stress along the belt path. Also, tethers allow the sides of the car seat to cocoon the child, rather than the sides flailing out, which typically happens when a seat is not tethered.

ST: Wow. Okay. So is there an easy way to figure out which car seats have lower anchors and which have tethers (and which have both)?
AB: Please use this table as a guide.

ST: Super handy. Thanks. Can you explain the deal with lower anchor weight limits? We’ve been hearing a lot about this lately.
AB: There is concern that the lower anchors in the vehicle may not be strong enough to hold heavier kids in heavier seats in some crashes. In a crash, it is the combined weight of the child and the car seat that pulls on and stresses the lower anchors. When LATCH was first conceived, there was no such thing as a 5-point harness for a child over 40 pounds, and most car seats weighed well under 20 pounds. Today, car seats typically accommodate heavier kids with some 5-point harnesses going up to 90 pounds. In addition, the car seats are heavier, too.

ST: Have there been any crashes in which the lower anchors have failed or broken?
AB: Not that anyone is aware of. If the lower anchors do have a maximum weight that they can withstand, we will see this problem manifested in real-world crashes only when there are more children using heavier car seats to higher weights. However, right now it is purely conjecture that the lower anchors have a maximum weight that they can withstand.

ST: So, what are the assumed lower anchor weight limits?
AB: There is no standardized weight limit—yet. Currently you need to know what your vehicle manufacturer says and what your child’s car seat manufacturer says (for that specific seat) to determine the lower anchor weight limits. This table lists the weight limits for the lower anchors as specified by each vehicle manufacturer, and is current as of June 2013. But please note, the information in the above table is taken from the LATCH Manual by SafeRideNews and may differ from the information found in your vehicle owner’s manual (in fact, your owner’s manual may say nothing about the lower anchor weight limits).

ST: Again, super helpful. Thanks. Now, what is all the buzz we’re hearing about a new LATCH weight limit?
AB: There is a major amendment to the Federal Motor Vehicle Safety Standard 213 (the safety standard that applies to car seats and boosters sold in the US) that is likely to go into effect February 2014. The amendment includes a new requirement that the lower anchor weight limits be 65 pounds—so when your child’s weight plus the car seat’s weight equals 65 pounds, you must stop using the lower anchors and switch to the seat belt. As part of the amendment, every car seat will have a label stating the maximum child’s weight for which the lower anchors can be used (so you don’t have to put your car seat on a scale and do the math!).

ST: So let’s say my child exceeds the weight limit of the lower anchors. Does that mean I have to buy a new seat?
AB: No! So long as the child is still within the weight and height limits for the car seat, you can continue to use the car seat, but must install it using the vehicle’s seat belt instead of the lower anchors. You should continue to use the top tether on every forward facing car seat as it significantly reduces the chance of brain and spinal cord injuries and it is the taller, heavier child that stands the most to gain from using the tether.  

ST: Do tether anchors have weight limits, too?
AB: Some vehicle manufacturers are stating weight limits on their tether anchors. As a pediatrician, this deeply troubles me as I try to practice evidence-based medicine and limiting the use of tethers exposes the child to proven risks in the hopes of preventing what remains only a theoretical risk (i.e., the tether breaking). Even if the worst case scenario should happen and the tether should fail in a crash, it is likely to break towards the end of the crash—after it has helped manage a lot of the energy of the crash—and would likely still offer significant benefit to the child. A potential risk to the tether breaking in a crash is that the metal hook at the end of the tether strap could fly and hit the child; however, without the tether, the child stands a significantly increased risk of hitting his head on hard structures like the window, door frame, or the back of the front seat.

ST: Do the lower anchor weight limits apply to boosters also?
AB: No. But first, let’s define “booster.” A booster is a seat the child sits on, and the child wears the vehicle’s seat belt as their restraint. If a child is using a 5-point harness from her seat, then she is not using a booster, and is instead using a car seat. Some booster seats now come with lower anchors. There is no weight limit to the lower anchors for booster seats because the booster is not the restraint and does not take the force of a crash.

ST: Okay. Do seat belts have weight limits?
AB: No. Seat belts are tested to withstand at least 6,000 pounds of force—and can hold even very large adults.
ST: What about using the lower anchors with the vehicle’s seat belt?
AB: That’s not a good idea. Unless the child’s car seat specifically allows this (currently, the Clek Foonf when used forward-facing is the only seat to allow this), you do NOT want to do this. Trust the manufacturer that they know their seat better than you do—if they don’t explicitly tell you to do something, don’t do it.

ST: Understood. So what should we expect to see happening within the car seat industry to prepare for this possible regulation on lower anchor weight limits?
AB: A few child car seat manufacturers are getting more innovative with the design of their seats to make it easier for parents to install the car seat with the vehicle’s seat belt, for children who are above the lower anchor’s weight limit. We’ve already seen a movement in this direction with the Clek Foonf (which uses rigid LATCH + seat belt + tether) and Britax’s new Frontier 90 and Pinnacle 90 (super easy seat belt installation), and the Safety 1st Go Hybrid (super lightweight, so weight limits unlikely to become an issue).

ST: Thank you so much for your help understanding these important safety issues, Alisa. We’ll keep an eye on your Facebook page and website for updates.