[alistairSH]

The article I read (this was a few years ago) wondered if the reduction in cycling (due to helmet laws created on safety grounds) actually ended up with the opposite effect. Fewer people outside cycling, more people in cars creating smog and getting fat. They didn't provide any data, just posed the question. I can certainly envision circumstances where that would be true, but you'd have to already have a very safe cycling culture (Amsterdam), I'd think.