I agree there's lot of traffic safety issues still (and I encounter them almost everyday too), but for a host of reasons that doesn't seem to translate into the same trends that the americans are seeing with increasing numbers of collisions.
Here's Toronto's serious automobile collision statistics (from
https://data.torontopolice.on.ca/pages/automobile). Obviously there's going to be far more minor collisions but the trendlines are moving in the right direction, if all too slowly.
View attachment 673396
To tie it back more directly to Line 5, my hope is that this means the various responsible bodies in Toronto are capable of taking measures that, at the minimum, over time, reduce number of collisions with the LRVs.
I've got to imagine increasing familiarity will play a role in safety too. When I saw them relatively close in-person for the first time, I was surprised how big the LRVs were. I was picturing in my mind sort of a larger streetcar but they are very much bigger and quicker moving.