A belt path refers to the track on the child restraint system (CRS) where the vehicle seat belt or the LATCH connectors strap go through to ensure the CRS is installed safely in the vehicle. A belt path can be divided into two which is the lap portion and the shoulder portion. Generally, the belt path for ECE CRS is different than an FMVSS CRS.
An ECE CRS when installed rear-facing usually requires a long vehicle seat belt. Local cars in the early years often has short seat belts. Parents who are using ECE CRS in old vehicles may have problems installing a rear-facing CRS due to the short seat belt. Furthermore, almost all of the belt installation of ECE CRS only allows installation with a 3-point seat belt.
For FMVSS CRS, a shorter seat belt is required for rear-facing installation. Some CRS also allows installation using a 2-point seat belt in rear-facing orientation. However, all FMVSS CRS when installed with a seat belt need to be locked either using the built-in “lock-off” or an additional locking clip if the seat belt does not have its own locking mechanism (read more about seat belt retractor here.)
Even though the belt paths are different between an ECE CRS and FMVSS CRS, each standard comes with its own pros and cons. Therefore, it is important to test the installation of the CRS in your car before you decide to buy it.