A single-occupant vehicle (SOV) is a privately operated vehicle whose only occupant is the driver. The drivers of SOVs use their vehicles primarily for personal travel, daily commuting and for running errands. The types of vehicles include, but are not limited to sport utility vehicles (SUVs), light-duty trucks, and any combination thereof, along with all the various van and car sizes, but would generally be taken to exclude human powered vehicles such as bicycles. This term is used by transportation engineers and planners. SOVs contrast with high-occupancy vehicles, (HOV) which carry many passengers.[1][2][3]
Single-occupant vehicles are seen as inefficient in many European cities, with officials and green activists citing unnecessary traffic congestion when carpooling and public transit are viable options. Single-occupant vehicles were banned for a limited time in New York City's Holland Tunnel following the attacks of September 11, 2001 - SOVs were seen as possible car-bombing resources for potential terrorist attacks.