I recommend the excellent book 'Traffic' - http://www.amazon.co.uk/Traffic-drive-what-says-about/dp/0141027398 http://www.amazon.co.uk/Traffic-drive-what-says-a

I recommend the excellent book 'Traffic' - http://www.amazon.co.uk/Traffic-drive-what-says-about/dp/0141027398 http://www.amazon.co.uk/Traffic-drive-what-says-about/dp/014... - it covers this pretty well.