Defining curve speed
You can define monotonically increasing speedcurve speed functions to specify different radii. With each of these radii, a speedcurve speed applies for the vehicle. These values are used in the following calculations:
- Automatic speed limit in curves, if this option is selected (Selecting network settings for vehicle behavior) Default curve speed functions for different vehicle types that are predefined in the defaults.inpx file (Default curve speed functions).
- Lateral drift speed and lateral deviation of the vehicle due to excessive speed (Using lateral drift speed).
In the Vehicles in the network list, you can display the Lateral deviation (excessive speed) of the vehicle (Displaying vehicles in the network in a list).
1. On the Base Data menu, click > Functions > Curve speed.
The list of defined objects for the base data type opens.
By default, you can edit the list (Using lists).
2. In the list on left, on the toolbar, click the Add button .
3. In the Name field, enter a name for the function.
The window of the function opens.
4. Click the start point or end point of the curve whose value you want to change, hold down the mouse button and drag the point to the desired value.
5. Right-click in the line.
6. From the shortcut menu, choose Add new point.
A node is entered.
7. Click the intermediate point and keep the mouse button pressed.
8. With the mouse button pressed, drag the intermediate point to the desired position.
9. Release the mouse button.
10. Confirm with OK.
The function is displayed in the list Curve Speed Functions on the left. In the Data points list, on the right, the minimum value, maximum value and the inserted intermediate points are displayed.
Element | Description |
---|---|
x |
Curvature radius:
|
y |
Speed: Speed for the given Curvature radius x. The function value is linearly interpolated between several interpolation points. The following applies for the lateral drift speed: The affected vehicle determines in each time step whether its maximum speed within the time step is above the critical speed. The smaller radius of the previous and next 3D point of the link are taken into account. Understeer can only occur if both 3D points have a radius > 0. The vehicle is carried out of the bend at the calculated lateral speed. If at the same time a deflection in the same direction is greater and the deflection is in the same direction, it affects the lateral movement. The vehicle attribute Lateral deviation (overspeed) indicates the lateral deviation in the current time step (Displaying vehicles in the network in a list). |
y(minimum), y(maximum) |
Speed: minimum/maximum speed for the given Curvature radius x. When used as a critical speed function: The values are ignored. When used as a desired curve speed function: a vehicle selects a target speed between y (minimum) and y (minimum) with y as the most frequent value in a normally distributed manner. |
You assign the function Curve speed as an attribute to those vehicle types you wish to impact (Attributes of vehicle types).
For curve speed, functions are predefined by default and stored in the defaults.inpx file (Default curve speed functions).
Superordinate topic: