With the current restrictions on testing and Ferrari always wanting more actual on track tests, i always asked myself why not build a secret underground track ? it doesn’t have to be a whole 5km circuit but big enough to test the aero of a car.
Is that really such a ridiculous idea? with the money Ferrari have i’m sure they have thought about it. Maybe RedBull actually have one :)
Well Who knows .They may even be having one , However it would be too expensive . Only the big three ( RBR , MCL , FER ) can afford one . Maybe RBR has a distinct possibility of having one as they indulge in a lot of sport activity and can cover up . However , with a state of the art design team and Wind tunnel capacity I doubt they would need one . Also transporting cars in and out will arouse a lot of suspicion . So my guess , not yet.
Assuming it were constructed from scratch, the cost of an underground test track would be enormous. A typical diameter road tunnel costs nearly US$100 million per kilometre to construct (source: an article in my local newspaper). Multiply that by the typical length of a test track, say 3km (the length of Fiorano), and the total bill comes up to US$300 million, equivalent to the entire annual budget of even the wealthiest teams.
Suppose the track were converted from a disused highway like Laurel Hill, the example Keith cited, or an abandoned bunker, as proposed by Abdurahman. Either way, you run into the problem of losing downforce within the confines of a tunnel, as mentioned by f199player and moshbeard. (Still a fantastic idea to dream about, though.)
There is already such facilities around the world but used for different purposes. For example here in Helsinki there are a number of “service” tunnels that are wide enough to allow a tank to drive through them. Maybe Marussia, could use Moscow’s “Secret Metro” to test :D (http://en.wikipedia.org/wiki/Metro-2)