As used in this chapter the term:
The term "motor vehicle" does not include any device which is used for livery, sightseeing, taxi, ambulance, funeral, or farm purposes; or any device with more than 3 wheels which is propelled by an internal-combustion engine, electricity, or steam and which has a seating capacity of more than 8 passengers, exclusive of the operator.
D.C. Code § 50-1702