Clause 12.4

In populated areas, the movement of vehicles is permitted at a speed not exceeding 50 km/h.

This clause establishes the general maximum speed limit within populated areas for all vehicles, including trolleybuses (unless otherwise specified by road signs).

Clause 1.10 (term “Populated area”)

Populated area — a built-up area, the entrances to and exits from which are marked by road signs 5.45, 5.46, 5.47, 5.48.

This term is necessary to correctly determine where the speed limit established by clause 12.4 applies.

Clause 33.5 — 33 “Road signs”, 5 “Informational and guiding signs”, sign 5.45 “Beginning of populated area”

Indicates the beginning of a populated area where the requirements of the Rules that regulate traffic within populated areas apply.

Clause 33.5 — 33 “Road signs”, 5 “Informational and guiding signs”, sign 5.46 “End of populated area”

Indicates the end of a populated area marked by sign 5.45.

Clause 33.5 — 33 “Road signs”, 5 “Informational and guiding signs”, sign 5.47 “Beginning of populated area”

Indicates the beginning of a populated area where, on this road, the requirements of the Rules regulating traffic within populated areas do not apply.

Clause 33.5 — 33 “Road signs”, 5 “Informational and guiding signs”, sign 5.48 “End of populated area”

Indicates the end of a populated area marked by sign 5.47.

That is, the correct answer is "50 km/h", given that according to the definition of the Traffic Rules, within populated areas (within the boundaries marked by the respective signs), the maximum speed for vehicles, including trolleybuses, must not exceed 50 km/h.

In this question, it is important to remember that a trolleybus is considered a vehicle under the Traffic Rules, and therefore, within populated areas, the general speed limit rules apply to it unless otherwise specified by road signs.

The Traffic Rules specify that a speed limit is established for vehicles in populated areas. This rule also applies to trolleybuses, so a trolleybus driver does not have the right to exceed the established limit just because it is a route vehicle. For example, even on a wide, straight city street, the trolleybus must comply with the general speed limit for populated areas unless there are signs allowing a different regime.

Thus, the maximum permitted speed for trolleybuses within populated areas is determined by the general limit set by the Rules for driving in populated areas.

Therefore, the correct answer is "50 km/h," since in populated areas the general speed limit for vehicles, including trolleybuses, is no more than 50 km/h.