 Minimum dimension for a vehicle to make a turn |
The turning radius (alternatively, turning diameter or turning circle) of a vehicle defines the minimum dimension (typically the radius or diameter) of available space required for that vehicle to make a semi-circular U-turn without skidding. The Oxford English Dictionary describes turning circle as "the smallest circle within which a ship, motor vehicle, etc., can be turned round completely".1 The term thus refers to a theoretical minimal circle in which for example an aeroplane, a ground vehicle or a watercraft can be turned around.
For the mathematical concept, see Radius of curvature.
The terms (radius, diameter, or circle) can have different meanings; refer to the § Alternative nomenclature section.