In Europe, usually only the driven tractor axle has dual wheels, while single wheels are used for every other axle on the tractor and the trailer. The most common combination used in Europe is a semi tractor with two axles and a cargo trailer with three axles, one of which is sometimes a lift axle, giving 5 axles and 12 wheels in total. This format is now common across Europe as it is able to meet the EU maximum weight limit of 40,000 kg (88,000 pounds) without overloading any axle. Individual countries have raised their own weight limit. The U.K., for example, has a 44,000 kg (97,000 pounds) limit, an increase achieved by adding an extra axle to the tractor, usually in the form of a middle unpowered lifting axle (midlift) with a total of 14 wheels. The lift axles used on both tractors and trailers allow the trucks to remain legal when fully loaded (as weight per axle remains within the legal limits); on the other hand, these axle set(s) can be raised off the roadway for increased maneuverability or for reduced fuel consumption and tire wear when carrying lighter loads. Although lift axles usually operate automatically, they can be lowered manually even while carrying light loads, in order to remain within legal (safe) limits when, for example, navigating back-road bridges with severely restricted axle loads. For greater detail, see the United Kingdom section, below.

When using a dolly, which generally has to be equipped with lights and a license plate, rigid trucks can be used to pull semi-trailers. The dolly is equipped with a fifth wheel to which the trailer is coupled. Because the dolly attaches to a pintle hitch on the truck, maneuvering a trailer hooked to a dolly is different from maneuvering a fifth wheel trailer. Backing the vehicle requires the same technique as backing an ordinary truck/full trailer combination, though the dolly/semi setup is probably longer, thus requiring more space for maneuvering. The tractor/semi-trailer configuration is rarely used on timber trucks since they use the two major advantages of having the weight of the load on the drive wheels, and the loader crane used to lift the logs from the ground can be mounted on the rear of the truck behind the load, allowing a short (lightweight) crane to reach both ends of the vehicle without uncoupling. Also, construction trucks are more often seen in a rigid + midaxle trailer configuration instead of the tractor/semi-trailer setup.