Which of the following types of vehicles is exempt from using seatbelts?

Motorcycles are exempt from the seatbelt requirement because they are designed for two-wheeled operation and not equipped with seatbelts at all. The law recognizes that the nature of motorcycle riding differs significantly from operating a four-wheeled vehicle. When riding a motorcycle, safety measures such as helmets are emphasized instead, given the lack of a protective cabin that seatbelts generally provide in other vehicle types.

In contrast, city buses, personal vehicles, and taxi cabs are designed without the same considerations for seatbelt exemptions, as these vehicles are meant to transport passengers in a more enclosed and secure environment where seatbelt use is crucial for safety. Thus, the requirement from which motorcycles are exempt reflects the distinct regulations applicable to two-wheeled transportation as opposed to the enclosed vehicle classifications.