Protesters took to the streets across Massachusetts to protest a grand jury's decision not to indict a white Ferguson, Missouri, officer who fatally shot an unarmed black teenager.  Dozens were arrested in Boston.Watch complete ABC News Interview with Darren WilsonThe largest protest was in Boston where an estimated 1,500 people marched from Dudley Square in the Roxbury neighborhood down Massachusetts Avenue to the South Bay. Police blocked a ramp leading to Interstate 93 to prevent the group from attempting to go on the highway.Photos:  1,4000 march in Boston protest | Watch reportMassachusetts state police said 51 people were arrested, primarily for disorderly conduct and disturbing the peace.  Most arrested were college students, police said."The crowd was rambunctious, but for the most part they were orderly. I am very proud of the job my officers did," said Boston police Commissioner William Evans. "We really took the soft approach. I don't think you've ever seen us with sticks and helmets. Even when we were being pushed at that line and being insulted, our officers stood tall."Many of those arrested appeared in Roxbury District Court to face disorderly conduct charges, most bargained down to a civil infraction.But for David Meredith, he claims the reduced charge came with a black eye."They put me in a headlock. They dragged me out of the protest group. They hit me in the face. They threw me on the ground. They handled it very poorly," Meredith said.Evans said Boston could be the standard for the next protest."I'd like to continue the dialogue so Boston can be a model of how protests should go, and the interaction can be a positive thing," Evans said. One state trooper was injured when he was bitten on the wrist by a protester.State and local police prevented the protesters from entering the Southeast Expressway and Massachusetts Turnpike.Uncut video:  Mass. Pike entrance blocked by police"We didn't want there to be chaos or panic on the Mass Pike last night," said Evans.  "We wanted people to be able to express their frustration and we also wanted people to express their feelings."A large crowd gathered at the Boston Police Department at 2400 Washington St. in Roxbury around 7 p.m., and began the march down Massachusetts Avenue and eventually onto the Massachusetts Avenue Connector, which leads to the Southeast Expressway.The protests were largely peaceful.“I’m very proud of the young people here,” Boston police Superintendent in Chief William Gross said. “Do you see any cars burning? Do you see any broken windows? No.”Police said they became aware of the pending protest by monitor social media, though they weren't sure of the precise location."We weren't caught off guard," said Evans.Smaller marches and protests occurred in other cities across Massachusetts, including Springfield, Worcester, Northampton and Pittsfield. All were reportedly peaceful.A community forum to discuss the events in Ferguson was held earlier Tuesday at the Twelfth Baptist Church in Boston. Among those attending were Boston Mayor Martin Walsh and Gov.-elect Charlie Baker.