My perception of the exact situation isn't clear, but . . . as one can read ON THE MASTHEAD OF THIS WEBSITE; lane-splitting, or lane-sharing by motorcycles, IS LEGAL IN CALIFORNIA
Don't know the OP's state of residence, but . . . the practice remains illegal in the other 49 states, AFAIK
If a motorcyclist should TRY the maneuver around here, the act would doubtless anger some 4-wheel vehicle motorists hereabouts, who might engage in dangerous retaliation.
I support lane-splitting where legal, and ACCEPTED BY THE MOTORING PUBLIC
, as it is generally under safe and prudent condtions, in California.
I DO NOT lane-split where illegal myself; YMMV!