An anti-police-violence protest planned for Friday evening by the Answer Coalition, beginning at Justin Herman Plaza — which they are still calling Chelsea Manning Plaza — is likely to shut down Market Street for a good while, depending on how many people show up. Calling for "Justice for Alton Sterling! Justice for Philando Castile! End Racist Police Terror!" the protest announcement notes that a parallel protest, the second after last night's, will be happening in downtown Oakland as well. (Curiously, Occupy Oakland posted about the SF protest, but did not mention the Oakland one).

If you're not joining the protest and intending to get home by Muni bus this evening, I would recommend leaving work on the early side.

People will be gathering starting at 6 p.m. at the foot of Market Street, and marching will begin sometime after that. Via the Examiner, we have a statement from San Francisco police spokesperson Officer Giselle Talkoff, saying that the department was warned by anonymous caller Thursday night that the protest tonight would become chaotic. "At this time, we’re still encouraging protesters to come out and exercise their freedom of speech. We’re just asking that it remains peaceful," she said.

The caller made no specific threat, only that things would get anarchic — which is fairly predictable given the kinds of things that have happened during other large protests here, like this one in the wake of Ferguson in late 2014. 79 people were arrested in that march, and the police confiscated a host of weapons and objects of destruction, like those below.

By contrast, Thursday night's march in Oakland was largely peaceful, though it did create a serious inconvenience for many hundreds of drivers who became stuck on the 880 freeway for upwards of three hours as at least a thousand protesters swarmed onto the roadway and blocked traffic in both directions.

The SFPD is certainly right to be concerned in the wake of last night's tragedy in Dallas, which took the lives of five police officers. Says Talkoff to the Ex, "Officers will be out around the protest making sure protesters are safe as well as rest of the public and fellow officers."

Related: Photos: 2,000 Rally Peacefully In Oakland To Protest Shootings Of Philando Castile And Alton Sterling