The design speed of an agricultural tractor being a part of a trackless train should be limited to:

This question is about the design speed of an agricultural tractor that is part of a trackless train. It should be limited to 25 km/h - answer B.

The Road Traffic Act defines a trackless train (kolejka turystyczna) as a vehicle combination consisting of an agricultural tractor whose design limits its speed to 25 km/h, or of a slow-moving vehicle, and a trailer or trailers adapted to carry people, used in tourist activities. A tractor for such a train may be approved for road use after an entry is made in the vehicle registration certificate that its design speed is limited to 25 km/h. The value of 20 km/h (answer A) is the limit for a tractor carrying a work crew in a trailer, and 40 km/h (answer C) is higher even than the general speed limit for an agricultural tractor on the road, which is 30 km/h. A trackless train usually carries children and tourists without seat belts, which is why the limit comes from the design and not only from the driver's discipline.

Legal basis: Art. 2 point 49a, Art. 20 para. 6 point 1 and Art. 71 para. 4a of the Road Traffic Act (Prawo o ruchu drogowym)