from memory 30m or 20m, it was enough if you where on the far side of a street you would still get it to avoid people running into the middle of the road.
Looks to me you went pretty much through all of them within a few metres- #3 was the only one not directly hit. Yeah, Maylands has a few hills to it away from the river :)
Looks like it was a more successful outing than the first time you used the site - thankfully!
After uploading it looked like we were in the all clear.