MIAMI -

More than 25,000 people are expected to attend the 28th Annual  Mercedes-Benz Corporate Run on Thursday.

Known as "Florida's Largest Office Party," roads are closing throughout Downtown Miami to accommodate the crowd.

"It's the biggest party in Miami. Everyone comes out here to run," said volunteer Ralph Garcia.

"The most runners, the most walkers -- for us it's very exciting," said race director Hans Huseby.

Metrobuses will be detoured around the route outlined below. For information regarding specific buses, click here.

The route starts on Biscayne Boulevard and Flagler Street the run travels south on Biscayne Blvd to Biscayne Blvd Way / SE 4th Street and west bound to SE 2nd Avenue then south over the Brickell Avenue Bridge to SE 13th St, west on SE 13th St. to SW 2nd Avenue, north on SW 2nd Ave to NW 1st Street, east on NW 1st Street to NE 2nd Avenue, north on NE 2nd Avenue to NE 4th Street, east on NE 4th Street to Biscayne Blvd culminating at Bayfront Park.

Road closures may begin on Biscayne Blvd. as early as 2 p.m. Roads are expected to reopen at 9 p.m.

Metrorail and Metromover will operate on a normal weekday schedule, from 5 a.m. to midnight.

Security will be beefed up this year following the Boston Marathon bombings.

"We're going to be adding undercover officers, put the bomb dogs out there, the bomb squad out there, and a lot more of our uniformed presence -- officers on bicycles throughout each home game of the playoffs," said Miami Police Chief Manuel Orosa. "For the Corporate Run, we as well we're going to be doing the same thing."

"There is measures in place already with the city of Miami. We feel confident and safe," added Garcia.

Participants have also been asked to leave bags at home.

Organizers hope the 5K circuit race will be a "first step toward fitness" for many participants.

Each year, a portion of the proceeds benefits the United Way.

For more information on the run, click here.