The family went out to dinner last night at a local Italian restaurant, and seated one table away was a motor officer with the California Highway Patrol. I decided to take advantage of this situation and ask for an expert's summary of the laws involving lane splitting. The officer was delighted to help and spent ten minutes educating me on the law:
Lane splitting in California is defined as riding between two lanes of traffic. The first infraction is obvious: riding between the right-most lane and the shoulder. The shoulder is not a lane of traffic, so is illegal to ride on or split.
The second infraction is not so obvious to most: the car pool (ride share) lane is separated from the main freeway by two solid yellow lines. This means that it is considered separate from the other lanes -- it is a different road entirely. Because it is only one lane, there is no other lane to split with. It is illegal to ride between the car pool lane and the left-most regular freeway lane.
I hope this saves you a ticket, and leave you with this:
Q: Why don't ride share lanes go under mountains?
A: Car-pool Tunnel Syndrome.