I think if I was an interstate trucker, I'd have a variety of experimental electronic hobby devices, reputed to inadvertently shut down cellphone connections, turned on at all times. I'm not, so I don't, but I've heard stories about those who do. Some truckers have some pretty high power CB amps too, so I wonder what running a cellphone noise jammer through a nice amp and high-gain antenna would do to a cellphone in the next car.
There were some problems at some airports near busy freeways, with unreliable GPS signals. They couldn't get some GPS approaches certified in spite of adding expensive GPS repeaters. They finally tried the brute-force method of sitting on the airport with a device reporting GPS signal quality, and observed. Turns out every time certain trucks drove past, the GPS signal became worthless. Some more investigation led to the realization that there are a LOT of truckers who use GPS jammers, probably to give the finger to their corporate beancounters who question every routing decision they make.
