Kids in the Koko NYC Soap Box Workshop program in Brooklyn put their creations to the test Saturday afternoon in the 15th annual South Slope Derby.

All summer long, the kids have been building soap boxes from recycled materials they’ve gathered to show off at the annual derby.

There were nearly 80 cars that the kids designed, built, and tested during a week-long workshop.  

Friends and families gathered to show support and cheer racers on. A panel of judges also gave out trophies based on creativity, design, engineering, and speed.