Utility Partners, Inc. 
Roaming Test
Sample Roaming Test Graph Product
The broad peak between 15h55 and 16h00 is in the area at the middle of the map where the vegetation is very dense, causing some strong loss of signal. Click here or scroll down to see maps of the area driven.
The point where the slime trail crosses maps to the wide peak of long round trip times on the graph, there are lower signal levels in that area due to the heavy vegetation.
The point where the slime trails cross is also a point where there was some base station jumping. In a full size map you can observe that the radio was moving back and forth between two base stations in that area. See below.
