Parents are more likely to use top tethers when installing a child restraint with a vehicle's LATCH system and attach the safety strap correctly if the attachment anchor is easy to find, a new study by the Institute and the University of Michigan Transportation Research Institute (UMTRI) indicates.
This is most often the case in sedans. Most tether anchors in sedans are on the rear shelf, also called the rear deck, behind the back seat, where they are easy to see. In SUVs and minivans, parents usually have to search for the anchors because they are typically on the floor, middle or lower seat back, in the cargo area or on the ceiling.
The findings complement earlier IIHS and UMTRI research of the key vehicle factors that make lower LATCH anchors easier to use (see "Keys to better LATCH," April 12, 2012).
It's well established that parents only use top tethers with forward-facing child restraints about half the time despite the fact that passenger vehicles have had corresponding anchors to attach the straps for more than a decade (see "Top tethers on child restraints are used less than half the time," Sept. 8, 2010).
Tethers are part of a child restraint attachment system called Lower Anchors and Tethers for Children, or LATCH. All forward-facing child restraints made since 1999 have a built-in top tether typically located just behind the upper back of the child restraint. Top tethers should be used with all forward-facing child restraints, whether they are secured by safety belts or with a vehicle's lower anchors. Some manufacturers also recommend using a tether with a few rear-facing child restraints.
In a 2013 IIHS survey, certified child passenger safety technicians observed parents and caregivers using the top tether 56 percent of the time with forward-facing child restraints. When parents neglected to attach the tether, it was most often because they didn't know about it. Using the LATCH lower anchors increased the likelihood that drivers would use the top tether. Child restraints installed with lower anchors were more than twice as likely to be tethered as child restraints secured with safety belts (see "Key child restraint strap is often overlooked, misunderstood by parents," April 25, 2013). This also was the case in the earlier IIHS-UMTRI study.
In the latest study, researchers recruited 37 parents and specifically told them to use LATCH to install two different forward-facing child restraints in four different vehicles for a total of eight installations. The 16 vehicles used in the study had a range of tether anchor characteristics
Parents used the top tether in 89 percent of the 294 forward-facing child restraint installations and attached the tether correctly 57 percent of the time. Because the instructions were designed to encourage tether use, the rate of tether installations was higher than recorded in field observations. Tether use rates improved from 83 percent to 95 percent after researchers in the study gave parents specific instructions on using LATCH and tethers halfway through their installations.
In sedans with tether anchors located on the rear deck, 95 percent of parents used tethers, compared with 79 to 89 percent of parents when the anchors were located on the floor, ceiling or seat back.
What's more, parents in the study were more likely to correctly attach tethers when anchors were on the rear deck or at the middle of the seat back than those located in other spots in the vehicle.
When vehicles had hooks for tying down cargo or other confusing hardware that could be mistaken for a tether anchor, the chances that parents would use and correctly install tethers were lower than in vehicles without such gear. This was most often the case in SUVs and minivans, while sedans were less likely to have confusing hardware. If parents did use top tethers in vehicles with confusing hardware, just 47 percent of the straps were attached correctly, compared with 70 percent of installations when there was no confusing hardware.