Sinclair C5 major consumer organisations published sceptical evaluations. The Automobile Association questioned many of Sinclair's claims in a report published at the start of May. It found that the range of the vehicle was typically only about 10 miles (16 km) rather than the promised by Sinclair, and reported that the C5's battery ran flat after only on a cold day. The C5's running speed was more usually around than the claimed , while its running costs compared unfavourably to that of a petrol-driven Honda PX50 moped. The stability, general roadworthiness, and especially the safety of the C5 were questioned, and the
Personal air vehicle breakthroughs. A ground transport alternative is enabled by unmanned aircraft technologies: Autonomous Systems and electric propulsion. Barriers include aviation safety, airworthiness, operating costs, usability, airspace integration, aircraft noise and emissions, tackled first by small UAS certification then experience. Other names discussed include PIVITOLs (Personal Vertical TakeOff vehicles), Air-cars, PACs (Personal AirCraft), AVs (Air Vehicles). The first technical paper to explain the difference in vehicle characteristics between PAVs and existing General Aviation single engine piston aircraft was "Personal Air Vehicles: A Rural/Regional and Intra-Urban On-Demand Transportation System" by Mark D. Moore (the NASA PAV Sector Manager) from NASA Langley Research Center.