Those of us the live here in California and have had to ride in heavy traffic have split lanes, I know I have probably more than I should have. I did have some close calls splitting lanes, and my opinion it really isn't safe, but there is also risk sitting in traffic as already mentioned. Reality is when I worked in the Bay Area the motorcycle cut at least thirty minutes off my commute time each day because I could split lanes. I never split lanes once the traffic was moving at a decent speed.
The real problem is the way commute traffic is it will be going 70 one minute and stopped fifteen seconds later, if the car or truck behind you isn't paying attention, and many aren't, you can get pancaked real easy.
When ever traffic came to a stop I always positioned my bike between lanes and many times at least moved up between the cars in front of me. Personally I think anything over 45mph is too fast to split lanes, but that is just me.
I can say this about most bay area drivers, they are so use to bikes splitting lanes most don't think much of it, and I have seen car actually move over to give me more room as I approached, but of course there were a few jerks, but very few.
opcorn:
