This is legal in California.....or it was when I was living there before moving in late '98.
It's perfectly legal in California for multiple vehicles to share lanes. For example. I can squeeze by you on the right if I am making a right hand turn and you are going straight. In fact a pet peeve of mine is morons that prevent this paticular activity by hogging the lane. ;-) Poor California we used to have the best drivers until all of the the illegals and Asians showed up :-(