This Sunday is the NYCRUNS Brooklyn Half Marathon. The expo kicked off Friday, as runners checked in to get their running bibs and T-shirts.

NYCRUNS founder and race director Steve Lastoe says there are about 20,000 runners this year.

"Right now, we're one of the largest half marathons. The real thing is taking that template for nonprofits and businesses in a way it isn't anywhere else," said Lastoe.

Road closures go into effect between 5 a.m. and 10:30 a.m. on Sunday. Parking restrictions start at 6 p.m. Saturday through 2 p.m. Sunday.

Click here for the list of restrictions.