It was Tracy's second win of the season and the 30th of his Champ Car career. Tracy, the pole winner, took control after a caution flag late in the race.
Two-time Cleveland GP winner Sebastien Bourdais was third and rookie Andrew Ranger finished a solid fourth.
In a minor incident, Ryan Hunter-Reay and Bjorn Wirdheim that came together near the back of the pack near the end.
The next event in the series is July 10 at Exhibition Place in Toronto.