AutoTURN: Intro for Traffic Project Work (Design Path Tools)

By Jacob Rojer, EIT

AutoTURN 10 by Transoft Solutions is a software program used to simulate vehicle drive paths on roadways, parking lots, etc. It is a quick and easy way to determine a vehicle sweep path and can help aid in the overall site design as well as catch potential site circulation issues early in the design process. We frequently use AutoTURN in our traffic projects for a variety of reasons, including checking:

• Truck circulation around a site
• Truck operations to/from the loading docks
• Parking operations, on- and off-street
• Intersection turning movements, like avoiding overlapping left turns

There are five ways to create a path in AutoTURN 10: generate arc path, generate corner path, oversteer corner path, steer a path, and place adaptive simulation. However, knowing when and how to use each of the design path tools isn’t always as clear. The following are some tips for using each design path tool in AutoTURN 10.

1. Generate Arc Path

The generate arc path tool is ideal for generating a path around curves on a roadway or irregular turns that require more than a single turn. When using this path generator, if the proposed path is part of a loading or parking area, be sure to check the “turn wheels from stop” box on the SmartPath Tools window. This allows for the steering direction to change while the vehicle is stationary (shown below).

2. Generate Corner Path

The generate corner path tool is used to create automatically create turning movement at a specified angle at intersections, access points, etc. To use this tool, a degree of turn can be entered manually in the sweep box on the SmartPath Tool or the adjacent “select sweep angle” button can be used to determine the angle required to complete the turn (shown below). To use the select sweep angle button select a reference line in the intended direction of the vehicle path, this will automatically calculate the sweep angle so the vehicle will be parallel to the reference line upon completing the turn. If there are no readily available guide lines then temporary lines may be drawn to help guide the vehicle path.  This tool is particularly helpful for reversing articulated truck movements, reverse movements use the same sweep degree function as the forward movements. An example is shown below.

3.Oversteer Corner Path

The oversteer corner path tool is similar to the generate corner path tool, the difference is that the oversteer corner path tool is ideal for articulated truck turns around sharp corners. The sweep angle functions the same as the generate corner path but there is the ability to enter offsets for the oversteer. For example, if the entry and exit offsets are set to 10 feet the generated truck path will swing out 10 feet at the start of the turn and then back in at the end of the turn to avoid cutting the corner on the turn. An example is shown below. This tool is very useful because the path preview provided allows for quick changes to the offsets and sweep angle without having to draw multiple paths.

4.Steer A Path

The steer a path tool can be used to create “free hand” vehicle paths. The vehicle will follow the cursor, therefore dragging the cursor in front of the vehicle will generate a path. This tool may be the fastest way to generate a path, however, it lacks precision and doesn’t easily allow for changes mid path as it doesn’t have a route preview function.

5.Place Adaptive Simulation

The place adaptive simulation tool is different from the other four vehicle path generation tools. To generate a path a reference guide line must already be drawn for the entirety of the desired vehicle path. When creating the guide line, it is important to keep in mind what the design vehicle will be. The radius of the curves in the guide path may not be smaller than the turning radius of the design vehicle if the design vehicle is following the guideline as a centerline, however there is also the option to offset the vehicle path from the guideline as well. An example of a guideline and the subsequent vehicle path are shown below. Once the vehicle path is placed, it is possible to move and drag the guide line to dynamically alter the drive path. This tool works well if it’s a larger vehicle simulation and the general vehicle path is known already or the drive path is relatively simple. It is not as practical when it comes to movements such as oversteering corner paths.

When creating a vehicle path, a combination of the generate arc path, generate corner path, oversteer corner path, and steer a path can be, and frequently are, used depending on the desired results. It is important to think about your end result and then choosing the appropriate method or methods to reach it.

Got any helpful Autoturn tips? Share your comments below.