Have a look at this page.
Its a page on the BBC site that tells you what there traffic levels are in comparison with the average. ATM it is showing 67% below average - as would be expected.
It obviously isnt relevent if there is a big news story breaking - and there will be other factors but I thought it was interesting.
http://news.bbc.co.uk/2/shared/bsp/h...s/html/map.stm