SmartPath Tools such as Generate Arc Path Simulation allow you to generate a vehicle turn simulation. This is done on the fly by moving the mouse in the direction of travel.

SmartPath Tools account for a vehicle's speed and for lateral friction and superelevation, as explained in the sections below.

Speed, Lateral Friction and Superelevation

The minimum turn radius of a generated path is determined from either the vehicle's minimum turning radius as calculated from the steering lock angle, or from a minimum turning radius calculated from the vehicle's speed, lateral friction and superelevation. The larger of these two radii is used.

Minimum turning radius as a function of speed, lateral friction and superelevation is calculated using the following formula:

Metric Units	Imperial Units
R = radius (m) V = speed (km/h) e = superelevation (m/m, e.g. 0.02 = 2/100) f = friction (e.g. 0.03)	R = radius (ft) V = speed (mph) e = superelevation (ft/ft, e.g. 0.02 = 2/100) f = friction (e.g. 0.03)

Default lateral friction and superelevation factors used in AutoTURN Online are based on AASHTO (2004) values. The default values can be overridden at the time a simulation is created.

Reverse Maneuvers

Reverse maneuvers are generally considered to be performed with single part vehicles and cannot be carried out by vehicles with more than two parts. Lateral friction and superelevation are not accounted for in reverse maneuvers. Reverse maneuvers are carried out at 6 mph (10 km/h) or less, speeds at which these factors should be negligible.

Pre-Drawn Paths

Turn simulations created from pre-drawn paths do not account for speed, lateral friction, superelevation, or steering wheel turn rate.

Only forward maneuvers are possible with pre-drawn paths. Reverse maneuvers must be carried out using the SmartPath Tools.

The path must be created using either a series of connected lines and arcs, or a single polyline.