Blocking traffic is not legal and is not a new practice for protesters. When protesters block traffic, they are engaging in civil disobedience, a term coined by one of America's earliest freethinkers and intellectuals, Henry David Thoreau.
While nearly everyone caught in a traffic jam caused by protesters becomes upset due to the delay, it is important to recognize that reporting on traffic conditions is a mainstay of local news stations across the country, while protests often get ignored. Blocking traffic means at very least making the local traffic report.
Although organized protests or marches can obtain permits to close streets, frequently protesters move from the permitted areas. When protesters block highways or streets that they are not permitted to be on, they do risk arrest. However, police are loathe to arrest peaceful protesters, even when they block traffic. The recent protest in Washington D.C. blocked a busy intersection for 7 minutes, and there were no arrests reported.
But What About the First Amendment?
The First Amendment guarantees the right to assemble and the right to free speech and expression; however, there are limits on those rights. Generally, local and state governments can and do restrict the time, place, and manner of protest. For instance, noise and time restrictions are particularly reasonable restrictions for residential areas. After all, even if you care about the protesters' cause, you don't want to be woken up at 5 a.m. to the sound of bullhorns (unless you're just that righteous).
Additionally, just because people are protesting, they are not given free rein to break already existing laws. Simply walking on the highway, or any roadway outside of a crosswalk, is considered jaywalking, which is a crime. Furthermore, most jurisdictions also have laws regarding blocking or obstructing traffic.
I Was Arrested While Protesting, Do I Need a Lawyer?
Frequently, protesters are arrested. While often protesters are simply detained in order for officers to effectively control a crowd, some protesters do get charged with crimes. If you are ticketed and released, or booked into custody, contact a lawyer right away as all criminal charges are serious matters that can have serious consequences.
Usually, protesters are charged with:
If you get arrested while protesting, it is important to forget your First Amendment right to free speech and remember your Fifth Amendment right to silence so as to not incriminate yourself. Anything you say can be used against you. You can be charged with a crime even if you do not think you did anything wrong. Demand to speak with a lawyer and don't answer the officer's questions (apart from providing your identification).