Animal rights activists chain themselves to a truck hauling animal specimens and refuse to leave.
Two groups on opposite sides of the abortion debate confront each other on a heavily trafficked Modesto street as their emotions and the risk of violence rise.
These were two of the scenarios the Modesto Police Department prepared for in three days of training.
The training sessions were held this past week at the Stanislaus County Sheriff's Regional Training Center.
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The course was taught by instructors from the Department of Homeland Security to instruct police officers on how to disperse crowds or make arrests when dealing with large groups.
"You get a feel for what it really might be like," said Modesto police Detective Steven Stanfield, one of the trainees. "The purpose is to ensure everyone's safety."
Stanfield said the instructors have a lot of experience in dealing with unruly crowds. Some of the instructors dealt with the street protests that shut down the 1999 World Trade Organization meeting in Seattle, he said.
Modesto police have not faced large-scale, unruly protests in recent years, but the department has had its share of disruptive partygoers leaving downtown nightclubs and bars on weekends.
The most notable was the 2006 Labor Day weekend clash between a large group of young people and police downtown.
The melee, which came after a hyphy music concert for teens ended with police arresting 17 people. Officers felt overwhelmed by the crowd and called law enforcement agencies throughout the area for help.
Police formed riot lines and used dogs to break up the crowd, later saying they were caught off guard by an event that spiraled out of control after 1,500 people showed up at a club with room for 200.
Several Modesto police officers who regularly patrol the downtown entertainment district took part in last week's training.
Stanfield, who sometimes is assigned to the downtown patrol, said police recently had to move out a crowd that had gathered around a fight that spilled out of a downtown nightclub and onto the street.
"We formed a skirmish line and we cleared the road," Stanfield said. "And I didn't have to lay my hands on one person. To me, that's a success."
Modesto police Sgt. Doug Ridenour remembers the department dealing with large, unruly crowds on Graffiti Weekend, when cruisers and thousands of onlookers took over McHenry Avenue.
Those days are gone, but Ridenour said there still is a need for this type of training to maintain tight discipline among the officers. He said the goal is to encourage crowds to disperse without arrests.
"I've been in large-scale situations where we have not had the training, and it didn't come off as well," Ridenour said. "Once we get trained and much more organized it's better for everybody involved, because we don't have splintered officers out there doing their own thing."
The training teaches officers to work in a coordinated way to overwhelm crowds with their presence. If the crowds refuse to disperse, officers move in using synchronized tactics to encircle, divide or push back crowds.
On Thursday, police officer recruits from the training center played the role of activists protesting cruelty against animals.
The protesters were blocking a heavily trafficked road and refusing to leave. The trainees were equipped with helmets, foam batons and gas masks, gear that would be used in a real incident.
The trainees put on their gas masks just before the instructors deployed smoke grenades to simulate tear gas.
"The whole world is watching," the protesters chanted. "Whose streets? Our streets!"
The instructors told the police recruits to shout and create the volatile atmosphere the officers would have to contend with in a real situation.
"These guys have to maintain their decorum," one of the instructors said about the trainees.
The trainees marched in a column before fanning out into a wide skirmish line and began to push their batons forward, slowly moving the crowd back. Other trainees then moved in small groups through the skirmish line to arrest protesters, one or two at a time.
The Department of Homeland Security offers this training to police across the country at no cost, Ridenour said.
"It's not costing us anything, except our time," said Ridenour, who worked for a few months with federal officials to bring the training to Modesto.
Stanislaus County sheriff's deputies also participated, along with other agencies in the region including the Merced County Sheriff's Department, Stockton police and an investigator with the Department of Motor Vehicles.
Ridenour said they invited the other agencies because Modesto police might need to call other agencies to help disperse a large crowd. He said communication is crucial in performing these tactical maneuvers, so they want everyone to have the same training.
Forty-five law enforcement officials participated in the training. About 15 were from Modesto police. Ridenour said they plan to arrange another training that will give advanced techniques on handling large protests.
For the past year, Modesto police has sent about a dozen officers to the Homeland Security training center in Alabama for the crowd control training.
With budget cuts and limited resources, the travel costs would make it too costly to train a large portion of the department, said acting Police Chief Mike Harden.
He said training money is usually one of the first items to be cut.
"There are precious few dollars to go around," Harden said. "It would be virtually impossible to send so many people to Alabama."
Bee staff writer Rosalio Ahumada can be reached at email@example.com or 578-2394.