What is the maximum speed the driver of a passenger car with a trailer is permitted to travel on this road outside built-up areas?

In the photo there is a dual carriageway outside a built-up area, with two lanes in each direction and crash barriers; a lorry is driving in front of you. In a passenger car with a trailer you may drive here at no more than 80 km/h - answer A.

The Road Traffic Act states that the speed limit outside a built-up area for a vehicle combination or a vehicle not listed in the group of passenger cars, motorcycles and lorries up to 3.5 t is 80 km/h on a motorway, an expressway or a dual carriageway with at least two lanes for each direction of traffic, and 70 km/h on other roads. A passenger car with a trailer is a vehicle combination, so the limit of 100 km/h from answer B, which a passenger car without a trailer has on such a road, does not apply to it; 90 km/h from answer C is the limit for a passenger car on an ordinary road. A trailer changes how a car behaves: it lengthens the braking distance, and at higher speed it starts to "snake", which ends with loss of control. That is why the limits for vehicle combinations are 20-60 km/h lower. It is worth remembering three numbers for a passenger car with a trailer: 50 in a town, 70 on an ordinary road, 80 on a dual carriageway, an expressway and a motorway.

Legal basis: Art. 20 para. 3 point 2 and Art. 2 point 49 of the Road Traffic Act (Prawo o ruchu drogowym)