LATCH study provides vehicle design guidelines

Child restraint installed by a study volunteer

Posted 04/12/2012

Installing child restraints can frustrate even the most capable of parents. A system called Lower Anchors and Tethers for Children is supposed to make things easier by standardizing attachment hardware, but a new study conducted jointly by UMTRI and the Insurance Institute for Highway Safety (IIHS) shows that many automakers aren't paying attention to the key factors that make LATCH work. Only 21 of the 98 top-selling 2010-11 model passenger vehicles evaluated have LATCH designs that are easy to use.

The researchers scrutinized LATCH hardware and rear seat designs in a range of passenger vehicles to determine the key vehicle characteristics that would help LATCH live up to its billing. They also conducted tests with volunteers installing child restraints to identify which features made it easier to do installs with LATCH.

"Our results provide design guidelines for vehicle manufacturers on how to make LATCH easier for parents to use," said UMTRI assistant research scientist Kathy Klinich, lead author of the study. "We were happy to see that most manufacturers tested have some vehicles that meet the new criteria."

The goal of LATCH is to increase the number of children who ride properly restrained by making child restraints easier to install. Consumers who drive 2003 and later model vehicles likely have encountered the system. LATCH has two distinct components: lower attachments on child restraints that connect to anchors at the vehicle seat bight (where the bottom cushion meets the seat back) and top tethers on forward-facing restraints that attach to anchors on the vehicle's rear shelf, seat back, floor, cargo area, or ceiling. Tethers help prevent child restraints from moving too far forward during crashes, putting children at risk of head or neck injuries.

Researchers identified three factors associated with correct lower anchor use: depth, clearance, and force.

Depth: Lower anchors should be located no more than 3/4 inch deep in the seat bight and should be easy to see.

Clearance: Nothing should obstruct access to the anchors.

Force: Parents should be able to install child restraints using less than 40 pounds of force.

All three factors are related and are good predictors of how well people are able to correctly install child restraints. Vehicles meeting the criteria were 19 times as likely to have lower anchors used correctly by volunteers compared with vehicles that don't meet any of the criteria.

"These are things that automakers can do to improve child restraint installations, and most of them aren't hard," said Anne McCartt, IIHS senior vice president for research and one of the report's authors. "Lower anchors can be designed so they are easy to use."

Read the IIHS news release.

Download the technical report LATCH Usability in Vehicles.

UMTRI is now offering services to assess LATCH usability in vehicles and assessment of vehicle child restraint fit. For more information, see LATCH usability testing services.