A Texas-based training program, called Interdiction for the Protection of Children (IPC), teaches law enforcement officers how to spot indicators of child-sex trafficking and conduct roadside investigations.

Among the warning signs: drivers who are older and unrelated to their victims, who tell unlikely stories to the police, or who possess illegal drugs in amounts consistent with personal use — to keep their companions docile. Victims, officers learn, often lie to the police in obvious ways, sometimes appearing scattered or nonsensical — telltale effects of fear and trauma. They continually try to make eye contact with their abuser, as if looking for signals or orders. And they frequently possess sex toys, condoms, lubricant and lingerie inappropriate for their age, reports the Washington Post.

Some of these details might seem obvious; but, surprisingly, before the development of the IPC program in 2009 by a Texas Department of Public Safety officer named Derek Prestridge, there was no comparable, comprehensive training program to help patrol officers — those most likely to encounter children in distress — identify missing, exploited or at-risk kids.

The success of the program has been, unavoidably, difficult to quantify. Before the creation of IPC training, Texas DPS kept no record of "child rescues." But as of February, Texas state troopers had made 341 such rescues since the program's inception; and in formalized follow-up interviews, virtually all of the troopers said the training was key to spurring them to action.