Most motorcycles do not have trunks or back seats in the traditional sense that you would find on cars. Motorcycles are designed with a focus on lightweight and compactness, which limits the amount of additional storage or passenger space.
Motorcycle manufacturers prioritize the overall design and performance of the motorcycle, and having a trunk or back seat would add weight and bulkiness, affecting the handling and maneuverability. Additionally, motorcycles have a smaller frame and fewer points of contact with the road, making it more challenging to accommodate additional seating or storage areas.
Some motorcycles, particularly touring or adventure motorcycles, are designed with features to provide additional storage options. These motorcycles may have built-in saddlebags, top cases, or panniers that can be used to carry luggage or other items. These storage compartments are designed to blend with the overall aesthetics of the motorcycle and maintain its streamlined profile.
As for passenger seating, most motorcycles are designed for one or two riders. The passenger seat, if present, is typically smaller and less comfortable than the driver's seat. However, there are motorcycles specifically designed for more than two riders, such as three-wheeled motorcycles or sidecar-equipped motorcycles, which provide additional seating capacity.
It's important to note that the availability of trunks, back seats, or additional seating/storage options can vary depending on the motorcycle model and manufacturer.