Yesterday I had a close call. I ride in EU on small roads among villages and most times I don't see any car traffic, which is partly due to the time of the day I choose to ride, usually towards the evening.

The roads are dry but in number of places, there is an occasional water run across it, sometimes just a wet patch with no water such a would splash when you ride over it. I crossed one such damp patch and headed into a mild right hand curve at about 30 kmph (almost 20 mph) and decided to slow down a little before entering the curve and my rear wheel locked and snapped sideways to the left quite a ways, at least a foot or likely a bit more and when I got full control again, I found myself on the left side of the road with only a few inches of asphalt on my left side. Luckily there was no oncoming traffic on these deserted roads but there could be.

I have recently switched the old Shimano brake pads to Koolstop ones that brake much better and that might be why I locked the wheel but the damp road patch likely was a contributing if not the sole factor.
Fall season means there are also leaves on the roads and old apples that fell on the road and where smashed to a pulp by passing traffic, occasional mud spots that fell of the wheel of tractors entering the roads from muddy fields, in short all the joys of fall season. Time to ride those downhills more conservatively. I suppose most US bike riding roads don't have none of these dangers, except wet patches and maybe leaves, unless you ride in some farming regions?