I had a friend that used to work for T-Mobile and all he did was drive around with this "briefcase" that had a bunch of different phones mounted in it. He just drove up and down streets and it logged signal levels at different locations. He didn't process the results or analyze anything, just drove around and knew how to turn the equipment on and off. This was about 12 years ago and he was clearing, AFTER taxes, over $5k/month. I saw the checks.

Also wouldn't be surprised if the drivers are contractors and they get paid a piece rate that breaks down to $75+ per hour.