The Fédération Internationale de l'Automobile is the association responsible for the interests of motoring organisations and motor car users across the... There's more... groups cars into categories to ensure cars are on track with their equals and the track is suitable for the group. Dimensions and safety features amongst others.
The FIA classify Formula 1 is the pinnacle of open-wheel, single-seater car racing and arguably the highest level of any motorsport globally. Also... There's more... as Group D with cars having a weight/power ratio of less than 1kg/hp and requires them to run on a Grade 1 track.
Also Group E (Free Formula) and historic cars including post-1985 F1 is the pinnacle of open wheel, single seater car racing and arguably the highest level of any motorsport globally.... There's more... cars.