Try to take some commuter trains in London, or buses, and you'll find plenty of people napping. At one job I preferred to take the bus to the tube even though the tube would be faster, because I enjoyed the longer unbroken nap.
There's even a comedy sketch (don't remember with who) about how London commuters are seemingly able to enter the tube, grab hold of one of the bars, and proceed to seemingly sleep standing for the exact right number of stops.
