Lawrenceville police this week said they will require groups to obtain permits before protesting in an effort to ensure the safety of participants.

In a statement, department officials said they had worked to “accommodate those wanting to express their emotions through impromptu marches and gatherings,” but planned to return to normal procedures for planned public events.

Those procedures require a permit for gatherings or to close roadways. They also allow for “spontaneous” events in response to news, as long as the city is notified at least 24 hours in advance and participants stay “on private property or a public area in a manner that does not unduly disrupt or inconvenience the public.”

Lt. Jake Parker, the police department’s public information officer, said the notice came after a July 4 protest in which two arrests were made: one of a pedestrian who wouldn’t stay out of the street and one of a driver who stayed in one place through several green lights to protect pedestrian protesters, then wouldn’t show identification when asked by police.

Parker said the city has made six arrests since protests started at the end of May.

“We support free speech, we really do,” he said. “We support free speech, but you’re not going to block the roads.”

Parker said officers have been more lax recently as protesters have often spilled off of sidewalks. But he said it is dangerous when cars and pedestrians mix, and city police will make more effort to ensure people are following the rules.

“You can’t just call it a protest and do whatever you want,” he said. “This has kind of been building up to us having to reiterate this message.”

Still, Parker said, he doesn’t expect arrests to increase dramatically, even if impromptu protests continue to occur.

“This is a reminder,” he said. “It’s not a warning.”