Blurred Traffic Stock

This was me fiddling around with shutter speed (at least to the extent that my camera will let me) to try and get a slow "exposure" for the blurred traffic effect.

I fully expect hurled insults on this one , so I've put on the Advanced critque option for the following reason: How do you (if you've done this kind of shot before) get the effect right? Is it a function of lengthy exposure for better camera's, or is there some sneaky trick to it?

As the usual, rules for stock in my journal.