Faster than a human would. Computers may be confused from time to time, but they don't need to rest or sleep and they don't get distracted by that cute body walking down the pavement in the summer.
Where they do fall down is in the very rare instance where two children or dogs were to come at it from different directions at exactly the same time. The computer would probably not be able to choose which one to avoid and therefore run them both over.
Computers are only as good as the programming they run. People on the other hand are as good as, well, the morning after the night before, how distracted they are, whether or not the phone rings or a message tone pings from sms or facebook, or whether they are smoking or had one too many at the pub before leaving.
I find it quite funny really. In my youth I read a lot of science fiction about how technology would be there to make our lives easier, remove the mundane, make it safer. How wonderful it would be to have all that time to one's self and be able to do other things.
Of course, when it truly arrives, reality invades. It's an encroachment on our lives, it's taking away our options, it's, well it's, well, bad.
Funny how life turns out isn't it.... One mans dream and all that.