PITTSBURGH (WPXI) — Sunday’s lineup is busy with the Pittsburgh Marathon making its big return after a 2-year hiatus, the University of Pittsburgh’s graduation and an afternoon Pirates game. There will be dozens of road closures scheduled and thousands of visitors flooding the city. With hundreds of signs posted and barricades ready to block dozens of roads, city police said drivers were warned to make way for the return of the Pittsburgh Marathon. “Over the last year, we’ve been working with fire, with EMS, Allegheny County dispatchers and the National Weather Service,” said Pittsburgh Police Commander Cristyn Zett. With hundreds of moving parts, officials have worked to clear a 26-mile path that spans several neighborhoods including the South Side, North Side, Shadyside, Homewood, Highland Park, Friendship, Lawrenceville, the Strip District and Oakland. “It’s going to be a very busy day in the city,” said Zett.