The writer seems to be confused about what constitutes a vehicle. I doubt that lights, horns, and licenses are included in any definition of a vehicle. I think Karldar defined it most succinctly and correctly:
If it transports a person/thing, it's a vehicle.
The trouble is, the government creates its own definitions. In my state of California, the vehicle code provides this one:
A "vehicle" is a device by which any person or property may be propelled, moved, or drawn upon a highway, excepting a device moved exclusively by human power or used exclusively upon stationary rails or tracks.
http://www.dmv.ca.gov/pubs/vctop/d01/vc670.htm
So, by this definition, a bicycle is not a vehicle (nor is a train for that matter). So, what is it then? According to the vehicle code, it is this: