I just want to preface that I am not blaming anyone ,or accusing anyone of, anything, just the catalyst for this conversation is that DW witnessed this piece of tragic news: and she says that had the child been wearing a helmet he would likely have survived. News reports also indicate he died from a head injury.
It is extremely rare in this neighborhood (romema) to see a child that age (5) wearing a helmet while riding a bike with stabilizer wheels, however in the city we come from it is almost universal (admittedly less so among the more yeshivish crowd.) I'm curious though what it is like in other places and if Israel is just different from the US in this regard.
My son is a similar age, and a similar bike.
We haven't been makpid on a helmet, sort of saying to ourselves that we need to get him a helmet tomorrow for a few months at this point etc... BUT he's only allowed to ride in carfree areas and needs to walk it to get it there.
If your wife really witnessed it, make sure she's ok. (Like for the next couple of weeks...). My wife was the first emt there when that poor kid was ironed by a cement mixer @ shamgar/torah mitzion and I made sure to be extra on top of her mental health for a while. (It was a BAD accident, her report back was basically major injuries, no need for additional volunteers).