So, I have one more appearance of the bridleway. It is on the server.exp.simutrans.com - (80,72) - near brewery Trnavan. That tile was owned by public player, public right of way, and is now within the town (just on the border), but may have not been when it turned to bridleway. It has the sidewalks, and is unowned now. The road tile next to it (in direction out of town) is in 99% condition, which means it was renewed recently, as there is quite some traffic on it.
The experiment setup at Bohdanovce has no result so far, but I expect the tile (128,99) to turn to bridleway or mothballed road soon, as it is in 25% condition.