All England, mostly London.
http://www.itv.com/news/london/2013-03-19/londons-slowest-roads-in-rush-hour/
"cars using Jamaica Road in Southwark between 8am and 9am last month averaged just 0.08 miles an hour. An average pedestrian would walk about forty times faster."
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"Our findings have revealed what a phenomenal amount of time many business drivers waste when travelling during the breakfast rush hour."
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I assumed that Jamaica Rd must be really short, but it's not. Some people must be spending serious amounts of time crawling along there.