Road and Lane

Use this dialog to set parameters for the cross-section, roadway, left side, median, and right side of the road as viewed forward along the roadway.

Where can I find the dialog?

In the toolset, go to SFI Properties - Properties - the Show button to the right of Road Class - Road and Lane.

Using the Dialog

Enter values for the surfaces out to the shoulder (shoulder to shoulder).

Illustration of road surfaces

Width Extensions

When driving in curves, a vehicle needs more space than on a straight road. The increased space requirement is due to tracking (bs), and parts of the vehicle may extend beyond the wheels (bo).

Illustration of width extensions

You can reduce the width extension or tracking that the design vehicle has in curves. Here, you also consider whether the vehicle should use the shoulder when driving in curves.

Width reduction specifies how much to reduce the width extension calculated from the selected vehicle.

If the road or lane is 3.50 m and the vehicle is 2.60 m, you can, for example, reduce the width extension by up to 0.90 m.

Steering addition is a safety margin for imprecise driving within the roadway.

The formula for width extension is:

Width extension = 2bs + 2bo + Steering addition - Width reduction (bs + bo for roads with a single lane).

bs and bo are calculated based on the vehicle's dimensions and curve radius, and thus cover all vehicles defined in the Gemini vehicle editor.

Interpolation length specifies the length for building up the width extension when you do not use clothoids as transition curves. This applies to the transition between a straight line and the calculated width extension based on the standard calculation of tracking in curves (symmetric width extension). For asymmetric width extension, the tracking calculation is followed completely.