I say a whacker.
They look like wide band military antennas. The spring bases seem to suggest that too.
A true military vehicle likely wouldn't be a consumer suburban. I could be wrong, but it looks like a 1/2 ton suburban, too. Most vehicles I've seen like that used by government are 3/4 ton.
The roof rack mounting is suspect. Again, screams "WHACKER". Real men drill holes. Government drills holes. Real installers drill holes. People who have jobs that depend on radios drill holes. People whose lives depend on radios drill holes. Throwing a sheet of aluminum across the luggage rack because you are worried about resale value, your wife forbidding it, or just not having the cajones to do it right, screams hobbyist/Wacker.
Might be interesting to search the HamSexy site and see if this guys shows up.
I doubt it's a cellular company drive test vehicle, the antennas are not suitable for the cellular bands.
Driving fast with a bunch of novelty oversized/phallic antennas with zero attempt to blend in doesn't suggest any sort of covert/secret squirrel/low profile. Looks like the Whacker Patrol out yelling "Hey, look at me!"