SAN DIEGO — Dozens of UCSD students brought traffic to a halt on northbound Interstate 5 Wednesday morning to protest the decision of a grand jury in Ferguson, Mo., not to indict a white policeman for killing an unarmed black teenager.

A crowd of an estimated 50 to 70 protesters marched onto the freeway at Nobel Drive at about 6:49 a.m., blocking the northbound lanes. They remained in the roadway for about 40 minutes until San Diego police arrived and removed them.

The protesters left the freeway peacefully and began marching on surface streets. There were no immediate reports of arrests.

The demonstrators, led by an unidentified man with a bullhorn, held signs objecting to the Missouri grand jury’s decision not to charge Officer Darren Wilson in the Aug. 9 shooting death of 18-year-old Michael Brown, who was unarmed but allegedly came at the officer and, at one point, tried to take his service weapon from him.

Before authorities arrived on the freeway, several stranded motorists exited their vehicles and yelled at the protesters to move. At least one frustrated motorist got into a brief physical confrontation with the man holding the bullhorn.

San Diego police continued to monitor the protesters movements as they marched on city streets.

“They’re using their first amendment right,” said California Highway Patrol officer Jakes Sanchez. “You just don’t want them to do it on the highway.”

Many of the protesters were students at UCSD. They said that they decided to block the freeway to make people pay attention to what they see as a pattern of institutional violence against black people in the U.S.

“I understand being stuck in traffic is frustrating,” said officer Sanchez, “but every situation is different. Our officers use their discretion and in this case they decided not to cite or arrest anyone because they complied so quickly with all our orders.”

“What led to this demonstration is the fact that every 28 hour a black person is killed by a police officer, a security guard or a vigilante, and it’s very unlawful,” UCSD student Brilon Cooper said. “Most often these black people who are murdered are unarmed and their killers go free.”

The protest at UCSD came on the heels of several other protests overnight, including one downtown in front of a federal building and another in City Heights where the protestors temporarily shut down Interstate 15.

According to the Facebook page of The group United Against Police Terror, they will hold protests until the end of the month.