It's not racing, but if there's a steep hill you will pick up some speed (it doesn't help that Christiania uses drum brakes not disk brakes). Also the whole point of a bike is that it's faster to go around than walk. Don't get me wrong I'm all in on cargo bikes and I used a cargo bikes for my kids in a hilly area for years (it was a leaning trike see my other post for what kind it was), but the trikes with the joint in the middle are just unsafe (yes I've also seen people tip over with them, and it really only requires a sharp turn where you have to accelerate a bit).