What defines a bicycle according to safety regulations?

A bicycle is defined as a wheeled vehicle propelled by human power, typically through the use of pedals. This definition emphasizes the method of propulsion—being human-powered distinguishes bicycles from motorized vehicles. Bicycles are designed for use on roads and paths, often requiring the rider to physically exert energy to move and navigate.

The other choices provide definitions that do not align with the established meaning of a bicycle. A wheeled vehicle without pedals indicates a different type of vehicle, such as a unicycle or a scooter. A motorized vehicle with two wheels refers to motorcycles or scooters that use an engine rather than human power. Lastly, a vehicle that can fly short distances falls outside the realm of bicycles, which are exclusively ground-based and designed for riding, not flying. Understanding these distinctions is crucial for recognizing the definition and regulations surrounding bicycles within safety contexts.