Originally Posted by
iamtim
So... in CA, the law does not specifically allow "lane commanding", but it's written in such a way that it can be read to allow it. The law specifically states that slower traffic (specifically those vehicles which are holding up five or more vehicles behind it) must pull over to the right and allow faster traffic (the aforementioned five or more vehicles) to pass, and specifically states that bicyclists must follow that law.
Actually the CVC (Calif. Vehicle Code) does allow cyclists to 'take the lane', i.e. to move farther left when the right hand lane is too narrow to safely share with an overtaking motor vehicle. It's one of the specific exceptions listed in the section that otherwise requires cyclists who are going slower than the normal speed of traffic to keep as far right as practicable.
The rule about pulling over when followed by 5 or more other vehicles is in a separate section of the CVC and doesn't mention bicyclists specifically, but they are implicitly included under the 'all rights and responsibilities of vehicle operators' provision. It also specifies that pulling over should be done at a spot where it is safe to do so - not at the instant when you first have 5 vehicles following. In practice, I find that it's extremely rare for a bicyclist to have 5 or more vehicles directly behind for more than a few seconds but would certainly look for a safe spot to move over if it happened.