Vehicle Turning Paths

The turning radius, or turning path, of a vehicle is the smallest circular turn that it can make. Measuring the diameters, and commonly the radii, of the inner and outer circular geometries that a vehicle is capable of turning within, the turning paths of various vehicles are calculated as standards used when designing roads, parking layouts, loading, and public service areas. Turning circles are used to evaluate how easily a specific car can make a U-turn or park.

Common Questions

How is a turning circle measured?
A vehicle’s turning circle is the radius (or diameter) measured by the outer wheels of the vehicle while making a complete turn.
What car has the smallest turning radius?
The smart fortwo (2016) has the smallest turning radius of a passenger vehicle at a radius of 22’10” | 6.9 m.

What is a typical turning circle for a passenger car?
A turning radius of 34’-35’ | 10.4-10.7 m is common for passenger cars today.

Vehicle Turning Paths

Layouts

Vehicle Turning Paths

Single-Unit Truck | Bus - 20' WB
Dimensioned drawing showing the requirements for multiple turning angles of a Single Unit Truck or Bus with 20' wheelbase

The turning path of a Single-Unit Truck or Bus measures the minimum possible turning radius necessary for performing a u-turn in a vehicle with a 20’ | 6.1 m wheelbase. Measuring the inner and outer radii of the 180° turn, a minimum inner radius of 28’4” | 8.64 m and minimum outer radius between 42’-43.5’ | 12.8-13.26 m should be provided for single-unit trucks and buses.

The turning path of a Single-Unit Truck or Bus measures the minimum possible turning radius necessary for a vehicle with a 20’ | 6.1 m wheelbase. Measuring the inner and outer radii of the 180° turn, an inner radius of 28’4” | 8.64 m and outer radius of 42’-43.5’ | 12.8-13.26 m should be provided.
Single-Unit Truck | Bus - 20' WB

*Under Development*

Height:
Width:
Length:
Depth:
Weight:
Area:

Outer Radius: 42’-43.5’ | 12.8-13.26 m
Inner Radius: 28’4” | 8.64 m

Vehicle Wheelbase: 20’ | 6.1 m
Vehicle Length: 30’ | 9.15 m
Vehicle Width: 8’ | 2.44 m

Drawings include:
Single Unit Truck | Buses (20' Wheelbase) Turning Paths plan

Details & Downloads
Passenger Turning Path - 90°
Dimensioned drawing of measuring the turning path and radius for a passenger vehicle to make a 90° turn

The 90° turning path of a passenger vehicle measures the minimum possible turning radius needed when designing parking, loading, and drop-off spaces. Measuring the inner and outer radii of the 90° turn, a minimum inner radius of 11’6” | 3.5 m and minimum outer radius of 19’2” | 5.85 m should be provided. Though the turning path requires a width of only 7’6” | 2.3 m, additional clearances should be provided whenever possible to accommodate a larger variety of car sizes and driver abilities.

The 90° turning path of a passenger vehicle measures the minimum possible turning radius needed for parking, loading, and drop-off spaces. Measuring the inner and outer radii of the 90° turn, a minimum inner radius of 11’6” | 3.5 m and minimum outer radius of 19’2” | 5.85 m should be provided.
Passenger Turning Path - 90°

*Under Development*

Height:
Width:
Length:
Depth:
Weight:
Area:

Outer Radius: 19’2” | 5.85 m
Inner Radius: 11’6” | 3.5 m
Path Width: 7’6” | 2.3 m minimum

Vehicle Wheelbase: 8’10” | 2.7 m
Vehicle Length: 15’6” | 4.74 m
Vehicle Width: 5’9” | 1.76 m

Drawings include:
Passenger Vehicle 90° Turning Path plan

Details & Downloads
Semi-Trailer Truck - 40' WB
Dimensioned plan drawing of the required layout and turning radius for a Semi-Trailer Truck with a 40' wheelbase

The turning path of a Medium-sized Semi Truck measures the minimum possible turning radius necessary for performing a u-turn in a vehicle with a 40’ | 12.2 m wheelbase. Measuring the inner and outer radii of the 180° turn, a minimum inner radius of 19’4” | 5.9 m and minimum outer radius between 40’-40’10” | 12.2-12.4 m should be provided for medium-sized semi trucks.

The turning path of a Medium-sized Semi Truck measures the minimum possible turning radius necessary for a vehicle with a 40’ | 12.2 m wheelbase. Measuring the inner and outer radii of the 180° turn, an inner radius of 19’4” | 5.9 m and outer radius of 40’-40’10” | 12.2-12.4 m should be provided.
Semi-Trailer Truck - 40' WB

*Under Development*

Height:
Width:
Length:
Depth:
Weight:
Area:

Outer Radius: 40’-40’10” | 12.2-12.4 m
Inner Radius: 19’4” | 5.9 m

Vehicle Wheelbase: 40’ | 12.2 m
Vehicle Length: 45’6” | 13.87 m
Vehicle Width: 8’ | 2.44 m

Drawings include:
Semi-Trailer Truck (40' Wheelbase) Turning Paths plan

Details & Downloads
Passenger Turning Path - 180°
Plan drawing with dimensions for the radius required for a passenger vehicle to make a 180° turn

The 180° turning path of a passenger vehicle measures the minimum possible turning radius for use when designing spaces for u-turns or turn-arounds within streets, parking lots, drop-offs, or service areas. Measuring the inner and outer radii of the 180° turn, a minimum inner radius of 14’5” | 4.39 m and minimum outer radius between 24’-25’6” | 7.31-7.77 m should be provided throughout the turn. Turning paths can use either curb-to-curb or wall-to-wall measurements based on whether the turning circles are calculated based on the outer tire or the outer front overhang. Additional clearances should be provided whenever possible to accommodate a larger variety of car sizes and driver abilities.

The 180° turning path of a passenger vehicle measures the minimum possible turning radius for u-turns. Measuring the inner and outer radii of the 180° turn, a minimum inner radius of 14’5” | 4.39 m and minimum outer radius between 24’-25’6” | 7.31-7.77 m should be provided throughout the turn.
Passenger Turning Path - 180°

*Under Development*

Height:
Width:
Length:
Depth:
Weight:
Area:

Outer Radius: 24’-25’6” | 7.31-7.77 m
Inner Radius: 14’5” | 4.39 m

Vehicle Wheelbase: 11’ | 3.35 m
Vehicle Length: 19’ | 5.79 m
Vehicle Width: 7’ | 2.13 m

Drawings include:
Passenger Vehicle Turning Path 180° plan

Details & Downloads

Related Collections

Layouts