The world is polluted with roads.
Montage_of_screenshots_that_are_hilariously_crowded_with_roads.jaypig
I was thinking that, similar to how destroying one wall segment causes a cascade effect of many wall segments being destroyed, when a decay hit (AND ONLY A DECAY HIT)destroys a road segment, it could cause a similar cascade effect, destroying multiple connected milestones. If a connecting milestone has additional roads, the cascade can't continue. Overall this would only affect unused and forgotten roads I think. Even roads I'm negligent on upkeeping still take forever for the ends to accrue decay damage, so this might not even help with the road burden of the world, but it would be a nice start!