Law enforcement officers across Baton Rouge are bracing themselves for the possible return of swarms of protesters in response to the U.S. Department of Justice's decision announced Wednesday not to charge two white Baton Rouge police officers in the killing of Alton Sterling, a 37-year-old black man.

Local and state officials said they are hopeful there won't be a need for arrests or a repeat of the use of military-style equipment — which were on full display last summer — but the police response will depend on how protesters behave.

"If protesters remain peaceful, if they don't cause damage, and they don't block roadways — they will dictate whether mobile force is deployed at all," said Lt. Jonny Dunnam, a spokesman for the Baton Rouge Police Department. Mobile force refers to riot gear, armored cars and other militarized tactics used by law enforcement.

"You won't see that at all, if protests remain peaceful," he said.

As early as Tuesday night, before a formal announcement had been made about the federal investigation, three women were arrested on felony charges for blocking a highway. The women, two from Baton Rouge and one from Texas, were protesting along with a couple dozen others on Airline Highway across from Baton Rouge Police headquarters, which also had been the site of protests last summer in the immediate wake of the shooting.

Two of the women, Kiara Jones, 19, and Krystal Sonia, 45, were arrested last July during protests.

The felony charges — aggravated obstruction of a highway — were an escalation from last summer, when protesters were largely charged with misdemeanor offenses for simple obstruction of a highway.

After conversations with the East Baton Rouge District Attorney's Office in recent months, Dunnam said, officers determined the felony charge is more appropriate than a misdemeanor summons for blocking such a busy, dangerous roadway.

But Mayor-President Sharon Weston Broome said the felony arrests were not intended to be a warning shot to others hoping to peacefully assemble.

"What happened last night as it relates to those individuals who were arrested has to do with what they did that was in line with a felony charge," she said, adding that one of the protesters was illegally carrying a concealed gun. "It was not a directive to have protesters who were protesting peacefully to be arrested."

Broome has stopped short of condemning last year's police response to the protests, but said recently there is "room for improvement" as the department handles upcoming protests. The previous protests happened while Baton Rouge Police was overseen by then-Mayor-President Kip Holden.

In another departure, there is also a new superintendent of state police. Former State Police Superintendent Col. Mike Edmondson was heavily involved in last year's protest security and critical of protesters whom he characterized as violent.

Maj. Doug Cain, state police spokesman, wouldn't comment on whether State Police expects to change its protest protocols, adding that Baton Rouge Police is the agency in charge.

Richard Carbo, a spokesman for Gov. John Bel Edwards, said State Police, if activated for protest control, "would do what they need to do to protect themselves and protect the community around them."

But he said all of law enforcement has since acknowledged some room for improvements.

"They are more aware, and even the Sheriff's Office said earlier that they weren't perfect and can make some adjustments," Carbo said.

In a Tuesday morning radio interview, Sheriff Sid Gautreaux said law enforcement is far more prepared to handle protests in the wake of the Sterling decision than it was after he was killed in July, adding that deputies, State Police and BRPD have spent the past several months training together.

"We haven't changed our position at all, law enforcement," he said. "We fully recognize anyone's right to demonstrate, protest, to march, we recognize their right to free speech. We're going to protect that right, but at the same time, we're going to protect everyone else's rights to keeping things peaceful….We're not going to tolerate any lawlessness, any violence or any destruction of property."

Last summer, there were at least two protests where law enforcement came equipped with military-style rifles, armored vehicles, and sound cannons. In one case police wore gas masks, but they did not release tear gas on the crowds.

During a July demonstration that spilled into Beauregard Town, the armored vehicles pushed protesters who were linking arms and blocking a narrow side road.

About 200 people were arrested during a weekend of demonstrations, some of whom were captured on video being thrown to the ground. District Attorney Hillar Moore III refused to prosecute about half of the arrests.

Ninety-two of the people arrested filed a class action lawsuit against the city and law enforcement for excessive force, wrongful arrests and violating demonstrators' civil rights. State Police, Baton Rouge Police, the District Attorney's Office and the East Baton Rouge Parish Sheriff's Office all settled for a total of $100,000. An unnamed police officer who was injured during a protest in turn sued Black Lives Matters activist Deray McKesson, whom the officer faulted with organizing the protest.

Last month, another lawsuit was filed on behalf of seven other Baton Rouge protesters from last summer by the New Orleans-based MacArthur Justice Center. The suit alleges that the protesters were injured and denied medical treatment while in jail and that their civil rights were violated by the officers.

"Peaceful protests of police violence should not be met with militarization and further violence," MacArthur co-director Jim Craig said. "We hope that law enforcement will respond better than they did in July. If not, we'll unfortunately be back in court."

The Baton Rouge Police Department has since signed a good faith agreement with the ACLU and a north Baton Rouge community group outlining how both the police and protesters are expected to behave in the event of more protests this month, Dunnam said.

"It outlines how we're supposed to handle ourselves and how protesters will handle themselves, and if protesters are peaceful there will be minimal police involvement," he said.

The agreement spells out that protesters can't block roads, engage in violence or damage property.

If protesters want to demonstrate in a roadway, they have to apply for a permit, which was an issue for some protesters last year who meandered beyond their permitted pathways.

So far only one protest permit has been filed on Spanish Town Road downtown for May 6, Dunnam said. It is awaiting approval from the mayor's office.

Two downtown events, the Live after Five concert on Friday and the Corked 5K race on Saturday evening, have been postponed. Police detailing was unavailable for the events because manpower is being reserved for protests.

Follow Bryn Stole on Twitter, @BrynStole.