Very interesting study - it does worry me though that the impression I got from reading thread before reading study was 'best not to let children walk unsupervised before 10 due to depth perception' because after reading study that is not my taking from it at all.

When I was a child we walked about crossing roads from about seven, we were taught never to cross if can see a car. If the road was always so busy that wouldn't be possible we weren't allowed to cross it, or had to use a crossing.

I will do the same with my two, we walk everywhere now DD 3.5 will always stop at road for me at helps see if anything coming. I don't cross if car coming no matter how far as an example (I live in an inner Mel suburb complete with trams and is doable if not in hurry). Both my husband and I have been shouted at for not having my DD restrained along our busy road (and she will walk outside of me on pavement which some disagree with) but she knows not to go on the road and never has (we saw a squashed possum and she doesn't want to end up like him she tells me).

Am not concerned by stranger danger at all, cars would be my biggest worry but they worry me less than not letting them develop independence.