Ahead of Washington’s first-ever Grand Prix this weekend, race organizers and federal officials have taken extraordinary safety measures to prepare the nation’s capital for high-speed IndyCar racing.

Organizers have welded down more than 200 manhole covers to prevent them from becoming dangerous projectiles as motorsport cars speed overhead at speeds exceeding 170 mph.

Interior Secretary Doug Burgum addressed the precautions in an interview, explaining the scope of preparations undertaken by Penske Corp. and the IndyCar series ahead of the Freedom 250 Grand Prix. Meanwhile, one IndyCar boss warned of ‘carnage’ near Washington’s historic buildings.

“The Penske team and the IndyCar series team that helped build this thing have taken every precaution,” Burgum said. “You’ll see these concrete barriers everywhere, the high fences. They’ve even gone so far as making sure they’re welding the manhole covers down so they don’t get sucked up like a vacuum when these cars fly over the top of them.”

Burgum said fans would be kept in designated safe zones, with large video screens set up across sections of the National Mall for spectators unable to get close to the track itself, and estimated that as many as a million people could pass through the area across the full race weekend.

IndyCar President Doug Boles confirmed the extent of the infrastructure work during a separate interview, noting that manhole covers along the 1.7-mile course had to be shaved down or filled with special epoxy to sit flush with the street before being welded shut, while several traffic lights were removed entirely to accommodate the layout.

Boles acknowledged the tight, technical nature of the course, which winds through downtown Washington past the National Mall, Smithsonian museums and near the Capitol building.

“It’s going to be hard to pass here,” Boles said, noting that five of the track’s seven turns are right angles. “Could be a little bit of carnage in this place.”

The disruption caused by the race preparations has frustrated some residents and commuters in the weeks leading up to the event.

Despite the disruptions, the event has been heavily promoted by the Trump administration as the capstone celebration of the nation’s 250th anniversary, following a summer that included a UFC match on the White House lawn, a state fair exhibition and a record-setting fireworks display.

President Trump is scheduled to take a ceremonial lap around the course in his armored presidential limousine, “The Beast,” and will wave the green flag to start Sunday’s race, according to Penske Corp. president Bud Denker.

First lady Melania Trump is expected to join him in the viewing stands. Organizers say more than 140,000 tickets have been distributed for the weekend, with luxury suites from sponsors including Delta, Gulfstream and Verizon priced as high as $250,000, and a “Champions Club” viewing option available for $5,000.