Here in east NM, lane splitting is not done because there just isn't that much traffic. When I lived in CA, the CHP had specific guide lines for lane splitting, but only on freeways and other limited access multi-lane highways. You are allowed to split traffic if traffic speed is below 30 MPH and you can't go more than 15 MPH faster than traffic speed. If a cop is in a bad mood, you may be required to signal for each "lane change" before crossing the lane line.
This is allowed simply because it causes much less traffic disruption than half the bikes in the county stalled in the middle lane with an overheated engine.
