I believe this is only for serious road traffic accidents. Continue wearing your vest if you believe it will stop drunks wandering under your wheels etc.

This study is about the “number of bicycle and motorized vehicle collisions” reported in such a way as to be collated by the Italian government’s National Statistics department.

None of my bike crashes, thankfully, have been sufficiently hairy as to require they be reported to the authorities. They would never have made it into a government database.