Making LATCH easier to use — and use correctly — is a goal of an ongoing child safety research program at the Institute. What researchers have uncovered in laboratory and field studies is that parents often struggle to correctly install child restraints using LATCH, and the reason why depends a lot on the location and ease of use of attachment hardware in vehicles. A new IIHS study conducted with the help of Safe Kids Worldwide reinforces prior work indicating that modifying LATCH anchor setups in vehicles could improve child restraint installation rates.
LATCH stands for Lower Anchors and Tethers for Children. Intended to make it easier to securely attach child restraints, LATCH has been required in passenger vehicles since the 2003 model year and on child restraints manufactured since 2002. There are two components: lower attachments on child restraints that connect to anchors at the vehicle seat bight, and top tethers on forward-facing restraints that attach to anchors on the vehicle's rear shelf, seat back, floor, cargo area or ceiling. Child restraints can be installed with LATCH or safety belts. Top tethers should be used with all forward-facing child restraints, whether they are secured by safety belts or using the lower anchors.
A 2012 study by the Institute and the University of Michigan Transportation Research Institute pinpointed three main vehicle factors that make the LATCH lower attachments easier to install correctly (see "Keys to better LATCH," April 12, 2012). The two-part study scrutinized LATCH hardware and rear seat designs in a range of vehicles and then had volunteers install different types of child restraints in vehicles representing different LATCH setups.
The three key factors associated with correct lower anchor use were depth, clearance and force.
- Depth: Anchors should be easy to find without digging around in the seat cushions to locate them. A common problem is that safety belt buckles, plastic housing or vehicle seats obscure or interfere with lower anchors.
- Clearance: Anchors should be easy to access, with enough space around them to accommodate child restraint lower connectors.
- Force: Parents should be able to easily clip or snap child restraint connectors onto vehicle anchors. Some LATCH systems require excessive force to attach the lower connectors due to interference from seat cushions or other hardware.
In the latest study, IIHS researchers set out to see if what they'd observed in the lab would play out in the real world with parents who participated in Safe Kids' car seat checkpoints during 2010-12 across the U.S. The findings dovetail.
Drivers arrived at the safety checkpoints with child restraints already installed in their vehicles. Among parents who installed child restraints using only the lower anchors or the safety belt, 78 percent were using the lower anchors and 49 percent were using them correctly. When lower anchors met the three installation criteria, 80 percent of parents used lower anchors and 53 percent used them correctly. When the lower anchors didn't meet any of the criteria, 65 percent of parents used them and 41 percent used them correctly. Restraints were nearly twice as likely to be attached correctly when installed with the lower anchors rather than with the safety belt (63 percent vs. 34 percent).
Using the lower anchors with forward-facing restraints increased the likelihood that drivers would use the top tether, too. Child restraints installed with lower anchors were twice as likely to be tethered as child restraints secured with safety belts (62 percent vs. 29 percent). The finding is in line with an earlier IIHS observational study of tether use (see "Key child restraint strap is often overlooked, misunderstood by parents," April 25, 2013).
At checkpoints, parents who drove cars were somewhat less likely to use the LATCH lower anchors. This might be because lower anchors are often easier to see and access in minivans, SUVs and pickups. In cars, parents often have to dig around in seat cushions to find lower anchors. Among vehicles at checkpoints, SUVs and minivans were more likely to meet all three lower anchor installation criteria than cars.
After accounting for lower anchor use, tether use and correct use rates were higher when cargo hooks or other confusing hardware easily mistaken for a tether anchor weren't present or when the anchor was located on the rear deck, which is typical in sedans. This finding is in line with an IIHS study released in February indicating that parent volunteers installing child restraints with LATCH were more likely to use top tethers and attach the strap correctly if the attachment anchor was easy to find (see "Easy-to-spot anchors boost tether use," Feb. 20, 2014). This was most often when anchors were located on the rear deck or at the middle of the seat back as compared with other spots in the vehicle.
Together, these studies confirm that specific vehicle features are associated with use and correct use of LATCH in real-world child restraint installations in a variety of vehicle models. The next step for the Institute is to explore a ratings system to evaluate LATCH setups in the vehicles families drive.
"Our research tells us that there are design changes automakers can make to help parents install child restraints correctly to provide the best protection for children in crashes," says Anne McCartt, Institute senior vice president for research. "One way to encourage manufacturer improvements is to develop a ratings system for LATCH, with the goal of getting more parents to use LATCH and reduce the chances for misuse."