They like to do things a little differently in America. This is the Laurel Hill tunnel (Not named after the Fugees singer - that's Lauryn) in Pennsylvania, and it forms part of the Chip Ganassi racing team's test facilities.
Originally intended as a railway tunnel, but actually used as part of a now-abandoned turnpike road when it was built in 1940, the mile-long road is now an underground test track.
Ganassi's cars - he runs IndyCar, NASCAR and Grand-Am operations - are run down the tunnel up to a set speed, then coast to a stop while the aerodynamic forces around the cars are carefully measured. There's also a turntable at each end so the cars can be sent along in either direction. We want one.
This video capturing the V8 rumble of what we assume was a NASCAR was taken by a walker wandering by the facility - hearing that sort of noise coming from beneath a quiet Pennsylvania is quite eerie.
You can also find out more about this cracking facility courtesy of a nice feature done by the fine chaps at Racecar Engineering magazine.
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