What is instructed by the following traffic signs?

1. Weight restriction – 60 tons.
2. Correct answer: Special speed limit: It is prohibited to drive faster that the speed limit that is indicated on the sign (in k.p.h).
3. Special speed: It is prohibited to drive faster than the speed that is indicated in the sign under foggy or hazy conditions.
4. It is prohibited to drive faster than 60 k.p.h during the night. During the day, however, it is permitted.

WhyA number in a red circle is the maximum speed, and an illuminated sign means the same as an ordinary one. It is not about weight or fog.