For this I apologize, but I hear this complaint from a lot of drivers as I do not ride so they seek this understanding with me, many of these same people I know for a a fact do not signal and are overall lazy and inattentive drivers as are many I see on the road daily. In normal conditions with attentive drivers which are what they are supposed to under California Law be it should be a perfectly safe practice. Not all bikers I have talked to say they would lane split or like doing so. This being said bikers make a calculated risk when riding a bike where by which most accident between a car and a bike thoroughly have the bike losing. The benefit is that it is extremely exhausting to ride a bike through bumper to bumper traffic and I see many bikers calmly ride through lane splitting in such conditions. They know the risks and take them when they are betting their lives that drivers are up to the level of competence that the law requires while drivers face very little responsibility in most situations for the accidents that would occur. So as such these people who take up less space per person and generate less traffic congestion than single passenger cars should by all means be trusted as a group who meet stricter licensing standard, to their judgements to pull such maneuvers in part for their own safety. This being considered the car drivers should be held to their legal responsibilities of using their vehicles as law permits and be mindful of the vehicles around them. The same likelihood of getting in an accident with any vehicle should be the same no matter what the vehicle, as any vehicle could be veering out of their lane and be occupying the same space that a lane splitting motorcycle would be.