Another very similar and insidious hazard, I found out to my chagrin accompanied with a rather large amount of pain, is trace moisture on top of fresh asphalt sealant. The detailed circumstances are rather dull to relate, but this was a little while after some scattered thundershowers had dissipated, yielding to strong sunshine. Although I had been drenched, the road and I myself were already completely dry (except for my own sweat) when I reached my destination, which happened to be an asphalt parking lot that had been resealed less than a week previously. Though I didn't see or appreciate it at the moment, there must have been trace moisture on top of the sealant. Upon turning from the road onto the parking lot, as soon as my front tire contacted the sealant surface, the traction went from normal to basically nothing, and I went down like a sack of potatoes.