What do these permanently illuminated signs mean?

Your answer is correct. The illuminated signs above the lanes provide important instructions for drivers on the highway:

1. The green downward arrow means you may continue driving in lane 1. This lane is open and safe to use.
2. The yellow arrow pointing to the right means that drivers in lane 2 must change to the right-side lane (lane 1) because lane 2 is closing or restricted ahead.
3. The red crosses above lanes 3 and 4 mean those lanes are closed and vehicles must not use them. Drivers should have already moved out of these lanes.

This system helps manage traffic flow and prevent accidents by clearly indicating which lanes are open, which lanes require a lane change, and which lanes are closed. Always follow such illuminated signals on highways, as ignoring them can cause dangerous situations and fines.