Adrian wrote:

Want to bet?

I was at a friend's flat in Paddington last night. As we arrived, he was
just getting out of the "black bus" he'd caught home from work. His
(extremely nice and far from cheap) flat has a large balcony overlooking
the A40. The Edgware Rd is barely 300yds away.

Well, that's a sample of one. Keep going and you might have something of
statistical significance.

E.