You got it: I'm confident about my lack of confidence. That's why I phrased it like that.
It is an educated guess, based on the fact that there is a fixed number (ten) of such dynamic depots, which is known from the game files, and each such depot belongs to exactly one city, and the fact that the number of active dynamic depots appears to always be smaller than the total number of dynamic depots. But what I wrote earlier is not necessarily the only possible conclusion here, hence the lack of certainty.
Or both. Or neither. In this case, it's clearly binary (either the roadwork is represented by the regular prefab or by the "disabled" prefab). Whether or not the cycle is random I don't know. In the prefab defs, these places have a setting "running_timer: (1000, 3000)", but the presumed existence of a timer doesn't rule out a random factor. Your guess is as good as mine.
Anyways, the point about random road events is that they can occur basically anywhere. This also happens to be the case for IRL roadwork. But I don't think this is the case for the dynamic depots. If true, this is a pretty significant difference between the two.
Um, multiple random events at the same location at the same time? That would certainly be a bug.
I suppose it may technically be true that random events are limited to specific locations as well, but if that is the case, we're talking ten (roadwork locations) versus tens of thousands (random event locations), so I'd say the point still stands.