The most common semi truck combination that is legal across North America. Depending on the types of goods moved, these trucks will pull van trailers (enclosed), flatbeds, or refrigerated trailers. By moving the trailer axles apart from one another, you can increase the amount of weight that can be placed on the trailer axles, but often trailer lengths are reduced (see the 5 axle spread tandem combination). Gross weights for this combination are a standard 80,000 lbs on the US interstate, but many US states and all Canadian provinces will allow heavier gross weights.
