The UAS child restraint system used in Canada is a slight variation on ISOFIX. It is fairly usual for the same system to have minor variations in different countries and to have a different specific name. In the case of ISOFIX we can find variations such as LATCH (used in the United States), or two Canadian ones such as CANFIX and UAS.
UAS stands for Universal Anchorage System. The hooks are available in all current cars in Canada and the anchors are in all cars manufactured after 1 September 2002.
The UAS is not a safer option for securing a CRS than the seat belt but it is easier to use and leads to fewer errors when placing and securing the child in it. It can be a superior system in certain cases, such as when you are using a rear-facing seat which is lighter and less sturdy. In such cases, in a crash the seat belt will tighten and the seat can rock sideways, which can impede its protective properties, although it is above all a comfort issue.
Another characteristic of the UAS is that it has its own child weight limit, which is specific to each vehicle manufacturer. For example, Honda has established a 40 pound limit (18 kg), while the majority of General Motors models establish a higher limit of 48 pounds (21 kg). This information should be included in the car manual.
Although this system is virtually the same as ISOFIX, subtle differences in the specific legislation of each country could mean that certain systems might be incompatible in some cars, among other matters. The fundamental purpose of universal anchorage systems, whether it is LATCH, ISOFIX or UAS, is to ensure that installation of the child restraint system is free from human error and is easy to install.
As mentioned in the article, a system with universal anchorage is not any safer than using a seat belt. A child restraint system's safety is better determined by other characteristics such as the materials used, whether it has side fastenings and a number of other specifications.