ROCHESTER, N.Y. -- Police worked to break up crowds and maintain order in the streets for several hours following the conclusion of the Puerto Rican Festival.

For years, city leaders and festival organizers have been careful to point out that the festival, held at Frontier Field, is not the problem. It's what happens afterward, usually along North Clinton Avenue, miles away.

Police say rocks and glass bottles were thrown at officers. Several objects were set on fire through the night. 

"Ultimately, we'd like to get to a point where this doesn't happen," said Rochester Police Chief Michael Ciminelli. "This has been going on for many years; this year, similar to other years, there were projectiles thrown at officers, and that's obviously an issue of concern to us."

Police say in all, 15 people were arrested, 11 for traffic related offenses, three for disorderly conduct and one for obstructing governmental administration.

A 21-year-old woman died after a crash on Remington Street. Because of the crowds on the city's northeast side, first responders had a difficult time getting to the scene.