Since 1993, FMVSS No. 208 has required that seatbelt assemblies include a means to lock the belt to allow secure installation of a CRS. While the introduction of LATCH means that this may not always be needed, many caregivers continued to install CRSs with seatbelts, even in seating positions equipped with LATCH. In particular, 2014 NHTSA labeling requirements indicate that the LATCH system should only be used until the combined weight of the CRS and child reaches 65 pounds. When this weight limit is exceeded, the CRS should be secured using the seatbelt assembly. The most common method of meeting the seatbelt lockability requirements is a device that switches the retractor from an emergency locking mode (ELR) to an automatic locking mode (ALR); the mechanism locks the retractor when the seatbelt is completely pulled out of the retractor.
An unintended consquence is over 200 reported cases where children and adults have accidentally switched seatbelt modes from ELR to ALR and have become entangled in the seatbelt (Sidman & Liteplo, 2015). At least two fatalities have occurred from an occupant being strangled by the locked seatbelt (SafeRideNews 2009). Additionally, adult passengers may inadvertently engage the ALR mode when webbing is extracted from the retractor due to upper torso movement. This can occur more frequently with larger occupants. In most adult cases this results in a minor comfort or convenience issue; however, some individuals experience heightened anxiety due to the sensation of being entrapped by the seatbelt system. Current systems require the occupant to unbuckle the belt and allow the webbing to retract fully to switch the retractor locking mechanism back to ELR mode. Repeated issues with inadvertent activation of the ALR mode may cause some passengers to refrain from using the restraint system. In addition, some of the occupants who have become entangled in the seatbelt have had to cut the belt to be extracted.
To prevent children using CRS secured by LATCH from becoming entangled in the seatbelt, the seatbelt should be buckled and switched into locking mode before performing the CRS installation with LATCH.