Which of the following is NOT considered a road user?

A cargo plane is not considered a road user because it operates in the air, separate from ground transportation. Road users are typically defined as individuals or vehicles that use the roadway system. This includes bicycles, pedestrians, and trains, as they all interact directly with roadways or railway systems. Bicycles and pedestrians share the road with motor vehicles, while trains run on tracks that often intersect with roadways. In contrast, a cargo plane is designed for air travel and does not engage with ground transportation systems, thereby placing it outside the definition of road users.