Not all green turned black.

Patches of Los Angeles Memorial Coliseum’s greenery still stand untouched by NASCAR’s asphalt. Beyond what would be the east end zone and what is now Turns 3 and 4, grass remains visible to the sun. Therefore, it continues to grow.

“One of the grounds guys was going over to cut the grass, but to get from his compound to that, he was pushing the lawn mower across the track to get to the other end,” NASCAR’s vice president of design and development, Martin Flugger, told NASCAR.com. “I wanted to take a picture of him with a lawn mower going down the track just because I’ve kind of cut him off from his work. He no longer has the field to take care of.”

There’s a quarter-mile asphalt oval race track in its place, carefully constructed over the football grid in a way the grass underneath should not be damaged. Even as NASCAR races its 2022 Busch Light Clash this Sunday (6 p.m. ET on FOX, MRN and SiriusXM NASCAR Radio). Even as 23 stock cars that each weigh more than 3,200 pounds turn 150 consecutive laps.

RELATED: Weekend schedule for Busch Light Clash

The bold idea, formally announced Sept. 14, 2021, but in the works since early 2020, became obtainable through collaboration among NASCAR, LA Memorial Coliseum and New Valley Construction. Ground broke Dec. 21, the first piece of SAFER barrier was installed Jan. 15 and track lines were painted Jan. 24. Any signs of the grass gridiron, hidden but not gone.

“It was definitely a challenge,” Flugger said. “Because in most cases, we would get rid of every bit of topsoil, every bit of grass, everything that could be compressible. Things that you wouldn’t want underneath the track all had to stay. So, you start having to think about how do you protect what they have here and build up a track within the middle of a football field.”

First, a thick plastic barrier of Visqueen sheeting was put down on the grass, turf and red dirt – basically the entire floor level of the stadium. Plywood was placed atop. Together, those layers make up 130,000 square feet of protection.

A sheet of geotextile woven fabric lies as a divider between the protective measure and track rumble. It prevents any slipping and sliding, too.

Crushed miscellaneous base – 9,200 cubic yards worth – gives the surface a majority of the depth. There’s a foot of the fill below the flat infield and four feet on the outside with 2.5-degree banking (determined by iRacing tests). Asphalt then covers everything — 6,900 square yards to pave the track and apron; 6,800 for the infield — adding another four inches deep.

“Putting it down was definitely very difficult,” Flugger said. “Removing the last, say, four to six inches is also going to be very fun because, again, you can’t just put a bucket down and basically start pushing. If you rip the Visqueen — basically kind of punch into the field — and you start pushing some of the stone and things down into the field and into the soils below the field, man, it becomes a problem for them.”

Said LA Memorial Coliseum general manager Joe Furin: “How big of a concern was it? It was less and less and less. We kind of outlined the standards thing, about putting the Visqueen down. … Then, as we had those discussions, (Flugger) understood it. Not a problem, no pushback. … It’s a different way of saying, when you deal with professionals, your concerns are minimized.”

RELATED: Photos of the LA Memorial Coliseum’s transformation

As a public facility, the LA Memorial Coliseum is no stranger to housing big events. Sure, the University of Southern California hosts the Trojans’ football games there and the Los Angeles Giltinis have made it their Major League Rugby home. But the LA Memorial Coliseum has also hosted two summer Olympics (1932 and 1984), two Super Bowls (1967 and 1973) and a World Series (1959). And those are just a few marquee sporting events.

The venue is also leased out for large-scale concerts: Rolling Stones, Pink Floyd, The Who, Bruce Springsteen and many other famous names. Most recently, Kanye West performed with Drake there Dec. 10. A large chunk of the miscellaneous base NASCAR used to cover the field was actually left over from Ye’s show.

Speaking of shared resources, Auto Club Speedway and Long Beach Grand Prix loaned NASCAR their walls, catch fences and SAFER barriers for the Busch Light Clash. Those complete the track construction.

An issue that arose because of the heightened platform, the LA Memorial Coliseum’s tunnel that usually coasts right onto the field level had to be paved so the low-riding Next Gen cars didn’t bottom out as they entered. A rather minor modification, though.

“That would really be, that I can think of, the only adjustment that has been made to the facility itself,” said Patrick Rogers, NASCAR’s vice president of marketing services. “Everything else is just adding some fencing, maybe adding some barriers and things of that nature. But really, really working to preserve that venue and keep it pretty much as-is, right? Because it’s so iconic.”

Coaches’ boxes will be reserved for NASCAR’s competition folks. The press box will serve its same purpose, while the home locker room will be the Media Center, a track-level option. The TV booth will be dedicated to FOX’s broadcast, and the away locker room will be available as a green room, if needed. The training room, along with its resources, will operate as the care center. The jumbotrons will be controlled by the programming team for entertainment purposes.

Everywhere and everything are fair game.

“We want to support (NASCAR’s) initiatives, not necessarily say, ‘Oh, you can’t do that’ or ‘the Olympic Plaza is sacred; where the peristyle is in the Court of Honor, that’s sacred, you can’t touch that,’ ” Furin said. “No, the building’s a living memorial, actively used for events, so we’d rather you incorporate it into the planning than to say that’s behind red-velvet ropes.”

That pass includes the ability to light the Olympic cauldron. NASCAR will, but when is a secret.

RELATED: Busch Light Clash format, entry lists and more info

The possibilities are endless. This is an exhibition event. It doesn’t have to follow the normal race-weekend protocol.

In some ways, it can’t.

Because of the abnormally small infield, teams must park their haulers in a designated parking lot outside the stadium. There’s not enough space for normal pit boxes either, so there will be no live pit stops. That prompted the scheduled halftime break for crews.

“I haven’t lost sleep, but I sit up at night just thinking about these things, things that just pop up,” Rogers said. “We talked about driver intros and somebody brought up like, hey, they’re gonna have to drive the cars and get them on the track for the final. I’m like, ‘Well, should we have the drivers do that? Go a little off the beaten path.’ ”

They’re already there. The regular path would have led to Daytona International Speedway, where the Busch Light Clash was previously held since its inception in 1979. It would have led to any existing race track, really. Not a football field.

“From an excitement standpoint, I’m more excited about this than even the Rolling Stones opportunities and some other things,” Furin said. “I think, because a lot of opportunities were … To use the Stones as an example, the Stones play 30 cities. They take the show, they drive to Indianapolis, and they put on that same show. I don’t want to use the word canned, it’s anything but. But this is truly a one-off.”

RELATED: NASCAR’s history of racing at stadium venues

It’ll also be a first in NASCAR’s modern era, which began in 1972.

NASCAR last competed at another sport’s stomping grounds in 1971 — Bowman Gray Stadium in Winston-Salem, North Carolina. The difference, Bowman Gray’s race track is a permanent fixture, encircling the football field rather than covering it. The venue actively hosts both grassroots races and football games to this day.

The LA Memorial Coliseum, meanwhile, needs NASCAR to clear out by Feb. 27 — Giltinis’ opening home match. The Trojans’ season then takes over Sept. 3. Grass is surely preferred over asphalt for both those teams.

“It’s all still there, yeah,” Flugger said. “I’m sure it’s not really happy with me at the moment because it’s been buried underneath, you know, Visqueen and dirt for over a month. But it’s still there.”