Children in Brisbane competed in the 10th annual derby on Saturday morning on San Francisco Street.
The derbie cars were built for originality and speed, with kids getting up to 19 miles per hour on their rides.
Noreen Leek, Brisbane's Recreation Manager, said the city originally hosted a derby race in the 60s. The event was revived a decade ago, she said.
"We don't see other cities on the Peninsula that host derby," Leek said. "So it's kind of what makes Brisbane unique and special."
Brisbane's 30th annual "Day in the Park" followed the derby, complete with pie eating and dog dress-up competitions, dunk tanks and bounce houses.
Community members emphasized the day as a special affair for family members and friends to get together and celebrate.