Zimmerman appeared unharmed as he walked out of the medical station at the racecourse and spoke to the crowd that had gathered.
The event is now in its 98th year and features multiple races to crown a champion of the oldest active trophy in motor sports.
Put on by the business community each July, the popular event offers first-hand experiences and demonstrations for students of all ages.
Some Detroit City Council members are worried about reported dwindling crowds on Belle Isle since the state takeover.
Called the Once Around Bell Isle Festival, the Aug. 9 event also will include live music, craft beer, food trucks and local vendors.
Belle Isle’s golf center is struggling since the takeover of the island by the State of Michigan.
Some city council members expressed concern that many Detroiters no longer feel welcome on Belle Isle.
“If you have warrants, you’re probably gonna get arrested,” on Belle Isle, state police say.
An enthusiastic crowd of race-goers attended Sunday’s Grand Prix race on Belle Isle.
Detroit businessman, IndyCar team owner and race promoter Roger Penske celebrated a win on Belle Isle Saturday.