“There is evidence that traveling between lanes of stopped or slow-moving cars (i.e., lane splitting) on multiple-lane roads (such as interstate highways) slightly reduces crash frequency compared with staying within the lane and moving with other traffic. Although lane splitting is allowed in just a few areas of the United States, notably California, it appears to be worthy of further study because it offers a means of reducing congestion in addition to possible safety benefits. It is widely used in many other countries.”
United States. National Highway Traffic Safety Administration, Motorcycle Safety Foundation (2000), National agenda for motorcycle safety, U.S. Dept. of Transportation, National Highway Traffic Safety Administration
I agree that when a road becomes a parking lot, it's okay to split lane on a cycle. I've done it in CA, very nerve wracking, but less so than sitting there with high heat coming off the engine, sweating, and surrounded by cars/trucks driven by increasingly agitated/annoyed/*issed off drivers.