I was out there a few days ago trying to add to the map. I didn't get signal very far from the tower, maybe a half mile at most, though I was not on the highway where the signal appears to extend a bit further.
The tower is very short, I'd say 50 feet. here's a photo of it, taken from maybe 50 feet away.
I'm not sure, but I think it takes a bit before your phone will connect to LTE, so if you are driving by, you might not ever see it.