Warnings were publicized about a series of events known as the "LA to the Bay" or "Cali vs everyone" sideshow moving north from Southern California over the weekend.
It's not clear which events were connected, but in Los Angeles there were several street takeovers.
At one, an LAPD officer was struck in the head while trying to clear an intersection near the Arts District downtown. She was taken to a hospital to be treated and then released.
This week the Los Angeles County Board of Supervisors is expected to discuss calling on multiple agencies to host a community symposium on street takeovers.