Car racing: getting data from the car to the pit?

[Terry Fox]

My brother-in-law does car racing as a hobby.  He is not a pro, but does 
race on most of the large tracks in the eastern US.  He asked me about 
possibly having a radio system to transfer data from the data 
acquisition dashboards in the cars to the pit in close to real-time.  
Apparently the data-acq systems have real-time USB data outputs, and 
update a half-dozen parameters every two seconds or so.  The tracks can 
be up to about two miles big, and I believe not line-of-sight, at least 
from the pit.

Sometimes the driver gets too busy to monitor the dash, and they want 
another set of eyes in the pit to monitor the parameters as well.  
Apparently the pro racers do have this capability, but I assume it's out 
of his price range to use their equipment.  I told him to check and see 
how they do it, what type radios, freq, etc...

He and my sister are both electrical engineers, and are comfortable with 
hardware & software, but not RF (and not hams).  I sent him a long email 
discussing radios, modulations, half/full-duplex, FEC, etc issues, along 
with a very basic, what frequency? information.

Does anyone know of a not-to-costly product that might fulfill this 
requirement?  Or another way to do it?

Thanks.
Terry