Speed differential is something I am aware of, but will certainly pay more attention to. I actually drove today, but I witnessed something that had the potential to be pretty bad. I was stopped (2nd car back) at the lights. There was a vacant lane to my right, and light traffic around. Everyone had stopped, because a stray dog was wandering around on the footpath. Sure enough, as the light turned green, the dog decided to enter the intersection. Along comes a ute, in the vacant right lane, and proceeded to enter the intersection at about 60km/h (the speed limit). He saw the dog at the last moment, and hit the brakes, wiping off a little bit of speed. He clipped the dog, and continued to skid, but was well across the intersection by the time he slowed enough. Dog was ok, and continued to cross, with a bit of a yelp! Anyway, the moral is, the ute was actually traveling 60km/h faster than the traffic around it, if you think of it that way, even though he was not braking any laws. If it was a bike coming though, or a kid running across, it could have been a fatality.