Concerned citizens and government workers in New Jersey's largest city are taking to the streets in an effort to reduce crime.

Under Newark's "Crime Caravan" program, volunteer convoys have been rolling through the city's roughest neighborhoods a few nights each week since Sept. 29. More than 120 volunteers in 45 vehicles hit the streets Monday, breaking off into five groups, called "packs." Each pack was led by an off-duty police officer in an unmarked car with flashing emergency lights.

It's about "waving the flag" and emphasizing that Newark is a city of laws again, according to Mayor Cory Booker, who initiated the trial program to damp crime this fall. Critics say the patrols are a political ploy by the mayor and could endanger the civilians who participate.

"The caravan gives people a sense of strength and security," said Booker, who is trying to fashion a national blueprint for renewal in a former icon for inner-city decay. "They let criminals know we're taking the city back."

The cash-strapped city pays nothing for the program, and supporters say it channels community angst about violence into a force multiplier for police. The packs look a lot like the multi-vehicle police impact teams _ known to locals as "trains" _ that are filled with heavily armed officers. Civilian volunteers aren't allowed out of the vehicles, most of which are white vans paid for with charitable donations.

The program also helps Booker politically by harnessing the same popular angst over community violence as his opponents, who have been holding anti-violence protest rallies in key city intersections.

John Sharpe James _ son of former Mayor Sharpe James _ is part of that movement. The former U.S. Army major views the caravan program as strictly a political ploy.

"I see no effect" from them on street violence, James said.

Jack Calhoun, a law enforcement consultant for the National League of Cities, said the citizen patrols are a novel way to elevate civic activism _ instead of just relying on the police to do everything.

"Community fear is a big issue in crime-torn areas," said Calhoun, who manages the California Cities Gang Prevention Network.

Jeff Walker, a criminal justice professor at the University of Arkansas, said the patrols advance two other law enforcement objectives by raising police visibility and disrupting the street drug trade by increasing "search time," referring to the amount of time it takes an illegal drug user to find a dealer.

"Anything that increases search time is good because some people will just give up," Walker said. "My only concern about the caravan is the potential for civilian injury once people on the street realize they're not trains."

Both Calhoun and Walker said they were unaware of similar programs in other cities.

Monday's caravan left at 11 p.m. _ just hours after Newark's 58th homicide of the year _ and returned after three hours on patrol. The five packs didn't make any arrests, but they garnered plenty of attention. For organizers, that's the whole point.

"The goal is deterrence," Newark Public Safety Director Anthony Campos said.

People loitering on the street moved quickly when the packs rolled through Monday night.

Six teenage boys were prowling the streets of a Newark neighborhood at around 12:30 a.m. when Booker's pack pulled up beside them.

"Come on guys," said Booker, 40. "It's way too late. Go home."

Recognition quickly gave way to smiles.

"Hey, it's Cory Booker," said one teen.

"Go home," the mayor repeated, impatiently.

"We are, we are," a second teen replied, explaining that the group had encountered a similar pack minutes earlier.

"We don't want any trouble," a third teen said.

The caravan idea is similar to a tactic Booker used as a city councilman, when he parked a motor home in troubled neighborhoods to disrupt drug dealing. The caravan lets people join him.

Some civilian participants are looking to make a difference. Others just want to spend time with a popular mayor who has become a celebrity after appearing on NBC's "Tonight Show," HBO's "Real Time With Bill Maher" and "The Colbert Report" on Comedy Central.

Joseph Gallant, 19, and two of his classmates from Rider University joined Monday's caravan after Booker mentioned the program at their school. The Newark native said he likes that the program provides motivated citizens with an outlet.

"You don't want a disconnect between citizens and police," Gallant said.

Booker hopes the caravan will help preserve the strides the city of 281,000 residents has already made in reducing shootings and killings. The number of Newark shooting victims fell 32 percent to 344 in 2008, from 503 in 2006. Homicides fell 36 percent during the same period to 67. Newark is on pace for fewer shootings this year, but more homicides.

Booker took office in July 2006. He succeeded Sharpe James, who is in prison for his role in the cut-rate sale of city land to a former mistress.

The mayor said the big test for the caravan program will occur on Halloween and "Mischief Night," a night before Halloween long associated with vandalism.

"Those are the two nights we're going to roll hard," Booker said.