Road signs, part 2

Almost everything about driving here is eminently orderly and civilised (except when I violate rules that I don't understand). My one major frustration is the lack of speed limit signs. When you enter Switzerland there is a big sign that says something like "120/80/50". OK, so 120 on the motorway--got that. Presumably it's 80 in the country and 50 in the cities, although where these boundaries are is unclear, but that's manageable. The problem is that on the motorway, when the speed limit changes there will usually just be one sign announcing the new limit (typically down to 100 or 80). If you miss the sign for whatever reason, you're potentially screwed. (Tunnels are an exception--that's the one place they give frequent reminders so you don't speed.) Then, when the reduced limit has been lifted and you can resume driving 120, you get one of the following signs:

So they don't tell you what the speed limit is, just what it isn't (and in the right-hand sign, they don't even tell you that). This is especially difficult on smaller roads. It's not 50, but is it 80? 100? There are no further reminders of the limit--if there are no speed reductions, they will never post a single sign. When you live here you eventually figure that out, but for people driving through on their way to Italy (i.e., half the population of Germany, the Netherlands and Belgium during the summer), Switzerland has a bit of a well-deserved reputation as a speed trap. I still view every drive I take where I don't see the flash of a speed camera as a rousing success.