Pontiac Michigan's M1 - a 1.5-mile road course, the first new road course in a major American metro area in more than a half-century.

A private-membership road course that is intended to raise $100 millions worth of “car condo” loft garages, retail, a corporate event center and a restaurant overlooking the track. So far it's cost about 35 million to get it to this point.

The track occupies a manufacturing site that dates to the 1800's. General Motors began building here in 1905 and the facility was finally torn down, in 2008, with GM's bankruptcy. The 87-acre property was bought up when GM hit rock bottom, and cut loose unused GM real estate assets.
Compared with middle-of-nowhere private tracks such as Spring Mountain, an hour North of Las Vegas, the M1 is in the heart of a big city, a 10-minute drive from the area's ritziest suburbs

The track also sits on the north end of Woodward Avenue, home of the annual Woodward Dream Cruise and the 1st concrete roadway in the USA.

http://www.thedrive.com/accelerator/6230/this-detroit-area-factory-ruin-is-now-a-racetrack

The site comprises 87 acres, and is the first new race track built in Michigan in at least 40 years.. Cooper Tire donated 25,000 tires to serve as crash barriers around the track.

The thick, concrete floors are rated for lifts, and buyers can build a mezzanine level to view the track, which can double as man-cave space, or anything else. The garages are heated and cooled, and if you do get a lift installed, it can raise up to that mezzanine level as a display car.

http://www.freep.com/story/money/cars/mark-phelan/2016/06/04/m1-concourse-pontiac-cars-track/85316488/
http://autoweek.com/article/car-life/m1-concourse-brings-road-course-racing-metro-detroit