[bert]

The auto contained a GPS transponder and was being monitored as it traversed I 40. When the signal ceased at the river the monitoring folks knew they had a problem.

Other guesses....

[rdavis84]

FYI

[zeaal]

Interesting ....

hmmmmmm ....

[eno_]

The auto contained a GPS transponder and was being monitored

GPS is, of course, not a two-way system. You still need another radio to get location data from a GPS in order to monitor a vehicle with a GPS locator on it. Not impossible, but not easy on rural interstates where cellular and even two-way pager networks are spotty. To get 100% coverage you would have to be following the vehicle within a few miles.

The story is damn wierd no matter how you slice it.