Charles, one of my students, came out for a night photography lesson in Shibuya on Tuesday. We did various things as excercises with using a tripod, including some shots from the overhead walkways near Shibuya Station. The main issue there is that the walkways have some flex, and they bounce... making long-exposures like this a bit tricky. Over a 30-second exposure, the flex in the walkway can throw the focus right off. So, we found a slightly more stable section of the overhead area - near where the lift is situated.
Charles shot some, I shot some. This was a 20second exposure at f/20... which is way too stopped-down for this lens, as at that aperture distant objects get soft. But, this shot had the best traffic trails on it. f/11 is about the optimum level of dof and sharpness on this lens. But, when I was shooting at f/20 I had forgotten I had a neutral-density filter in my bag. Doh! 20seconds was a good length of espoxure, so when I had remembered about the filter, I shot a bunch more at f/11 and 20seconds. Much sharper but the traffic had thinned-out a fair bit so the trails weren't as good.
Tokina 11-16mm f/2.8
One RAW file, split into three shots, 1-stop apart and then blended in Photomatix
Change to red and blue channels in Photoshop, to bring out the red of the car lights.