LogFAQs > #960879807

Yes, of course they do. In the same sense that seatbelts work - we still put airbags in cars because neither work perfectly, but combined (along with other measures like speed limits and the way we design traffic flows, intersections, etc.) their use will reduce harmful outcomes.

This is more or less how Layers of Protection Analysis works in hazardous industries like refineries, any plants where hazardous materials are manufactured or handled, chemical processing facilities, etc.