Not sure if youre being sarcastic, but this sign in Germany means that all previous (velocity) restrictions are lifted and the overall speed limit is valid (on "Landstraße"/country road => 100 km/h, "Autobahn"/Highway => theoretically unlimited km/h... well you still have to drive "according to the circumstances" which is important in case an accident occurs, so visibility, rain/snow, only two lanes etc.).
There is no direct context to parking.
Ehh...that doesn't necessarily pan out either. If I have no stimulation at all, my mind can swirl to 10001 different thoughts. What often works for me, personally, is to put on a YouTube video on my phone to help fall asleep. The trick is you want to find a long, relatively boring and not engaging one to sort of lull you to sleep. Make the mistake of putting on something too interesting and you're fucked.
That's me, anyway. I don't always need thought distractions to sleep but often I do.