If you drive a car whose length is up to 6 m, what's the maximum speed at which you can drive on a road once you go past this sign?

In the photo you can see a dual carriageway in fog, and on the right a blue sign D-7 "expressway" with a "1000 m" plate. When driving a bus up to 6 m long, you may travel on this road at a maximum of 80 km/h - answer C.

The Road Traffic Act sets out that outside a built-up area a bus may travel at a maximum of 80 km/h on a motorway, an expressway and a dual carriageway with at least two lanes in each direction, and at 70 km/h on other roads. The length of the bus does not change these limits: a vehicle designed to carry more than 9 people including the driver is a bus, even if it is only 6 m long. That is why the 80 km/h limit applies to it on the expressway, and the same speed is already allowed now, because before the expressway begins you are driving on a dual carriageway with two lanes in each direction. The values 60 km/h (answer A) and 70 km/h (answer B) apply to other roads or do not come from the rules for a bus. The "1000 m" plate tells you that the expressway begins in one kilometre, so as you approach it, remember your limit. In fog you drive more slowly anyway.

Legal basis: Art. 20 para. 3 point 2 letter a and Art. 2 point 41 of the Road Traffic Act (Prawo o ruchu drogowym); § 48 para. 1 of the Regulation on road signs and signals