I usually try to run on the road as opposed to the pavement, as you'd expect from anyone that doesn't want to end up with crippling injuries at 40 ;)
However, recently I had to run on the pavement for the entire 5-mile "my house to uni" route, due to the traffic being so heavy. What really surprised me is that it felt a lot more comfortable than running on the road - my feet hurt less. This is of course the opposite of what I expected!
Now, previously I'd suspected the roads' camber was causing foot pain, but hadn't given it much though. However upon stopping to compare it to the (level) pavement I discovered it was quite severe!
So, in my case it looks like I've found an even WORSE surface to run on than concrete, and I'll have to stick to the pavements unless I get up at 3am when the roads are empty...