How long is a Work Zone?

As I rode back into Woodstock this afternoon on South Street from the west, I came up on 30MPH Work Zone in front of the District 200 maintenance buildings. Although I was fairly sure that there was no construction in progress on a Saturday, I slowed down. Thankfully, the car behind me slowed down, too.

Shortly after that sign, just around a bend, is a standard, regulatory, 40MPH speed limit sign. Now what? Do I speed up to 40? Keep it at 30 for the Work Zone?

Then I spotted a construction area off to the left on a side road, and then beyond that was the Work Zone speed limit sign for oncoming traffic. Could I speed up there?

It's hard to ride a motorcycle with your fingers crossed, but I was still hoping to see an End Work Zone sign. I never did.

So the question is, where does a Work Zone end, when there is no End Work Zone sign? Is it at the point where oncoming traffic reaches its first Work Zone speed limit sign?

Wouldn't it be appropriate to erect End Work Zone signs in both directions?