sweptpath

Swept path refers to the envelope traced by the outermost points of a vehicle as it follows a prescribed maneuver along a reference path. In road and traffic engineering, swept-path analysis is used to determine whether a roadway, intersection, or other facility provides sufficient space for a vehicle to complete a turn or maneuver without conflicts with curbs, medians, or other obstacles. The concept applies to a range of vehicle types, from passenger cars to buses, trucks, and emergency vehicles.

Process and methods

A swept path study begins by selecting a vehicle type and size and defining a reference path, usually the vehicle’s centerline. The vehicle’s geometry is specified (length, wheelbase, width, front and rear overhangs), and a kinematic or geometric model is used to simulate steering as the vehicle follows the path. As the vehicle moves, the model traces the envelope formed by its outermost points, producing a two- or three-dimensional swept path diagram. The result is checked against available clearances, such as curb lines, building setbacks, lane widths, and obstacle margins. The analysis may be performed with specialized software or integrated CAD/GIS tools.

Applications

Swept-path analysis is used in designing intersections, roundabouts, driveways, parking layouts, loading docks, and service vehicle routes to ensure safe and feasible maneuvers. It assists in determining minimum turning radii, driveway throat widths, curb radii, and sight distances, and is essential for accommodating larger vehicles in urban and rural settings.

Limitations

As a planning tool, sweept-path analysis assumes standard vehicle configurations and steady-state maneuvers in a plane. It may not capture driver variability, load effects, vehicle cargo, or dynamic effects, and may require supplementary three-dimensional modelling for vertical clearances.