Chicago Public Schools today released maps of “safe passage” routes where security will be provided for 13,000 children whose elementary schools were closed.

The district plans to station 600 adults armed with cell phones and fluorescent green vests along 53 new routes, mostly around grammar schools CPS has designated as “welcoming schools.”

Safety was a key concern for people who opposed the school closings. But Chicago Police Supt. Garry McCarthy said Friday the city is prepared.

“This is nothing new in the city of Chicago,” McCarthy said at a weekly “transition briefing” that includes Chicago Public Schools and other city agencies. “Kids have been crossing gang lines for years to go to school. We have a program in place that’s very clearly worked. We’re doing more of it this year based upon the school closings.”

The district is doubling its spending on safe passage—to nearly $16 million per year. Until now the program has mainly focused on high schools.

The additional safe passage workers will be trained in de-escalating conflicts and recognizing problems before they occur.

School officials say they’ve seen a 20 percent reduction in reports of crime around schools with safe passage, and a 27 percent reduction in crime involving CPS students.

Correction: An earlier version of this story misstated the number of new safe passage routes. Chicago Public Schools officials gave reporters an inaccurate figure at the transition briefing Friday morning. They corrected the number late Friday.