There are two notable exceptions. First, as kids get heavier, most car seats require you to use the seat belt rather than the lower anchors of the LATCH system, as the seat belt is stronger. Second, car seats that feature rigid LATCH—rather than a lower anchor strap—are typically safer when installed with rigid LATCH vs. the vehicle’s seat belt. For most seats, it isn’t safe to use both lower anchors and the seat belt at the same time. While you must, in most cases, choose between the vehicle seat belt or the lower anchors (part of the LATCH system), tethers are used in addition to the vehicle seat belt or lower anchors for every forward-facing installation. That’s right: Whether your forward-facing car seat is using the seat belt or the lower anchors, you always add the tether strap to secure the top of the forward-facing car seat. A few rear-facing car seats also use tether straps.
Using the Seat Belt to Install a Car Seat
The vehicle seat belt can always be used in the traditional way, where it is routed through the belt path of the car seat and buckled in. The seat belt holding a car seat must be locked at all times, which means the belt can not loosen at all. This is very different from how our seat belt is when we ride; it only locks when you slam on the brakes. All seat belts in the US since 1996 have a way to lock themselves in order to be used with a car seat. Most feature a mechanism where if you pull the seat belt slowly out to the very end, as you let it back in it will continue to lock and shorten. It only switches back to normal when you let the belt back in all the way. Some car seats have built-in locking devices for the seat belt that often make installation easier. The seat belt also needs to be tightened, so that the car seat moves less than one inch in any direction when checked at the belt path. Using seat belts has a few advantages:
Seat belts are easy to find in any vehicle you encounter. You will also be prepared in case you need to install the car seat in an older vehicle that doesn’t have the LATCH system. (However, an older vehicle will likely be quite different and more challenging than a newer car. If the vehicle is pre-1996, it most likely won’t have the locking mode built into the seat belt. Also, older vehicles without LATCH won’t have tether anchors, and therefore aren’t suitable for forward-facing installations.)You can install the car seat in more of the rear seating positions, since you aren’t limited to positions with lower anchors.Some car seats feature built-in seat belt lock-offs that are easy to use. These built-in lock-offs allow you to lock the seat belt without needing to understand if the seat belt has its own locking mechanism or how that works.Some car seats feature seat belt tensioning devices, many of which also lock the seat belt. These tensioning devices often significantly reduce how much force is needed to tighten the seat belt.
Even if you’re fairly familiar with various seat belt systems and how they can be used to install a car seat, you should check the vehicle owner’s manual. It will tell you how to lock the seat belt if necessary and will give any important installation details specific to your vehicle.
Using LATCH to Install a Car Seat
The LATCH system has multiple components. The lower anchors are metal U-shaped or horizontal bars. These are sometimes hidden inside the vehicle’s seat crease, and sometimes are visible sticking out from the seat crease. Most vehicles have two sets of lower anchors, one on the driver side and the other on the passenger side in the back. A few vehicles may have sets of lower anchors in all three backseat positions. Often the center seat in the second row and many positions in the third row (in vehicles with a third row) will not have lower anchors. Most vehicles do not allow you to borrow the innermost lower anchors (belonging to the driver and passenger seats) to install a car seat in the center; the spacing is not the same. Even if you have one of the few vehicles that allow this, make sure you are using a car seat that allows this. There may be a tag, button, or imprinted lower anchor symbol to tell you where the lower anchors are in the vehicle. Even if you can easily locate those lower anchors, you should still read through the LATCH section of your vehicle owner’s manual. It will give you installation advice specific to your vehicle. The Car Seat Lady has information on where you can find the lower anchors and tether anchors in any American vehicle made from 2000 to 2020, including which positions in the vehicle have these anchors and which don’t. This table also shows which vehicles have center LATCH and links to a list of the car seats that allow themselves to be installed with lower anchors that are spaced wider than standard. The tether anchor is the second part of the LATCH system in your vehicle. It may look like the lower anchors, but there’s only one per set of lower anchors. In an SUV or minivan, the tether anchor is most often found on the back of the vehicle seat where the car seat is installed. However, in a sedan it is always on the shelf below the rear windshield. A few vehicles, most often SUVs or station wagons, have a tether anchor on the ceiling above and behind the back seat. The vehicle owner’s manual can give you the exact location of any tether anchors in your vehicle. With a few exceptions (such as convertibles or cars without back seats), there will be a tether anchor to go along with each set of lower anchors, and there is almost always at least one additional tether anchor, as well, that can be used along with a seat belt installation (tethers must be used for all forward-facing installations, whether with lower anchors or seat belt). For pickup trucks, the tether anchors may look vastly different than in other vehicles. They may even be loops of webbing instead of metal. You must read the vehicle owner’s manual to learn how to use this type of tether anchor. It is one of the only types where more than one car seat could share an anchor. The other parts of the LATCH system are on the car seat itself. Car seats have a way to connect to the lower anchors. Most use a strap with some type of a hook that connects to the vehicle’s lower anchors. A few car seats have rigid LATCH where the connectors are rigidly attached to the frame of the child’s car seat and there is no strap involved. All forward-facing car seats have a tether strap, which is a strap with a hook on the end that comes from the head of the child’s car seat and connects to the tether anchor in the vehicle. A few rear-facing car seats also use tether straps. For some car seats, rear-facing car seats in particular, another advantage of installation with the lower anchors is that the car seat won’t tilt to the side due to pressure from the shoulder portion of the vehicle’s seat belt. A seat belt installation where the seat belt’s built-in locking mode is used will often cause a tilt. A seat belt installation using a built-in seat belt locking device on the car seat (which means you don’t have to use the seat belt’s own locking mechanism) won’t tilt the car seat. A few car seats offer amazing ease of installation with LATCH. Seats with rigid LATCH (which are less common) offer a much easier installation than those with a lower anchor strap. Consult the car seat instruction manual for information on the specific LATCH pieces on your car seat, including how to route the lower anchor strap if it is a convertible car seat. The stickers on the side of the car seat will also give some basic directions on LATCH usage for your particular car seat.
Seat Belt vs. LATCH: Which Is Safer?
The safest installation method is the one that offers the most secure installation (the seat moves as little as possible, always less than one inch in any direction). If you want to install the car seat in a rear center position, that usually requires using the seat belt. Most vehicles do not have a set of lower anchors dedicated to the middle seat, and most do not allow the use of the inner anchors from either side for installation in the center. Check the vehicle owner’s manual to see if this is allowed. You’ll also need to consult the car seat owner’s manual to see if the manufacturer approves of the use of their seat with non-standard spacing of lower anchors. You may have heard that the center seat is the safest, which is true, statistically, though only slightly. A passenger can’t take a direct hit in the center. Sitting in the center reduces the risk of injury from about 0.28% to about 0.17% for kids three and under. So while it is safer, it is just a tiny bit safer. But if it is easiest for you to install your baby’s car seat correctly with LATCH, it is perfectly acceptable to use one of the outer seating positions to do so when LATCH is not available in the center or doesn’t work well for you there. If the vehicle manufacturer put lower anchors and tethers in the outboard spots, they clearly intended for children to ride there, and the vehicle has been tested that way. Your child’s weight also affects the safety of the installation method. Car seats are labeled with a maximum weight for installation with the lower anchors. The maximum weight for a lower anchor installation may be different when the seat is used rear-facing than when it is turned forward-facing. If your child’s weight exceeds the weight limit for using the lower anchors to install that particular car seat, you’ll need to switch and use the seat belt to install the car seat. Remember to continue using the tether strap on forward-facing car seats, whether you are using seat belt or lower anchors for the installation. The car seat manual will give details on when to switch between LATCH and seat belt.
A Word From Verywell
Before you decide how to install your child’s car seat, try out all of the possible seating positions with the seat belt and with lower anchors, if available. Get guidance from the vehicle owner’s manual and the car seat instruction book. Find a car seat safety event or technician in your area if you need additional help. Bottom line: The safest installation method is the one that you are able to get the tightest installation and is approved by the car seat and vehicle manufacturer.
