But can people be "victims" if they sell their bodies for sex — and keep some of that money or trade it for drugs? Are they victims if a pimp provides cell phones, buys them clothes, or even cars, or places to stay? In some instances, a prostitute might even have children with her pimp.
"Do we believe that people who make bad choices are victims?" Carr asks.
Often they are, she believes. But sometimes she says the public — and the people who are supposed to enforce these new laws — still have a difficult time seeing prostitutes as victims, even when they're young.
One recent Friday morning in a stuffy, crowded classroom at the Cook County jail in Chicago, a few women shared stories at a meeting of a group called Prostitution Anonymous. If they agree to get help, the women usually are not charged with prostitution in Cook County, though they may face other charges, from drug use to disorderly conduct.
Sheila Johnson, a 33-year-old inmate, told her peers how she had a difficult time breaking free from a boyfriend who was also her pimp, even though she feared him. She was addicted to drugs — and, she admitted, "the money."
"As a regular person, I wouldn't dare do the things that I did because I was on drugs," Johnson said after the meeting, as tears streamed down her face. "Being sober, I wouldn't DARE prostitute."
Tiffany Schipitz, a 35-year-old inmate, said she eventually escaped from a pimp who threatened to kill her if she didn't work for him.
"I'd never been put out on the street. I'm a white suburbanite girl.. That was unheard of growing up," Schipitz says, describing how she fled the car of the first man who came to pick her up for sex. Eventually, though, she ended up back on the street, high, looking to earn more money for drugs.
"The next thing I know, I'm out on that corner, taking cars — one, two, three — like it's nothing," she says.
These are the sorts of stories Sgt. Craig Friesen, head of the vice unit for the police department in Anaheim, Calif., hears often.
"I never met any prostitute who said, 'This was my ultimate goal in life,'" Friesen says. "They've all been brought into this life by someone. They've been exploited by someone."
When determining who's a victim of trafficking, though, his officers are trained to look for signs of coercion. They might ask a hotel clerk if the prostitute was not allowed to speak, or seemed frightened, when checking into a room. They look for bruises and other signs of abuse and bring in former prostitutes to do the interviews.
"You can dig more deeply and ask specific questions," say Friesen, whose department began working with a local social service agency in 2010 in hopes of getting help for prostitutes and cutting the number of repeat offenders.
Department statistics show that from August 2011 through October 2012, Anaheim police arrested and charged 38 pimps. In that time, the department also got help for 52 women who were determined to be victims of human trafficking — and thus, were not charged. Of those, four are known to have returned to prostitution.
Carr, at the University of Michigan, says she hopes more departments will focus on screening prostitutes, female and male, and training officers to recognize the signs of trafficking.
"Really good screening can't take place 10 minutes after an encounter with a law enforcement officer. The victim needs to be put in a safe place," Carr says.
"There are lots of incentives to not say what's happening to you."
But even when officers determine that help is needed, there's often not much they can do.
"Victims assistance is the weakest link in the chain," says Mark Ensalaco, a trafficking expert who's director of the human rights studies program at the University of Dayton.
He recalls one case, in recent years, when a young woman was rescued after an Ohio state trooper stopped a car on the interstate and recognized that she was a victim of sex trafficking. Beyond abuse, those signs can include malnourishment, having few possessions, avoiding eye contact and not having control of personal identification, such as a driver's license or a passport.
This woman, too, was addicted to drugs, Ensalaco says, but never got the help she needed. Eventually, she committed suicide.