Network-wide signal optimization considers the interactions between signalized nodes (Fundamentals: Network-wide signal optimization). The optimization aims to adjust signal times so that vehicles can pass several successive signal controllers when the signal is green. Optionally, you can combine the optimization of the offset times with an optimization of the cycle and/or split times.
1. Make the desired changes on the Basis tab.
|
Element |
Description |
| Run analysis only | If the option is selected, only an analysis of signal controller offset times is performed. |
|
Run analysis and optimization |
If the option is selected, you can specify whether you want to optimize offset times, offset times and green times, or offset times, green times, and cycle times, in addition to the analysis. Not all combinations are possible for signal group-based signal controllers (Fundamentals: Network-wide signal optimization). |
| Optimize lead/lag (only RBC) |
If the option is selected, lead/leg green stages are optimized for RBC-controlled signal controllers. |
| Precision of the offset times |
Enter the desired accuracy for the offset times: 1s, 0.5s, 0.2s, or 0.1s. |
| PrT path set |
To influence the optimization, you can define a PrT path set and assign a weight to the paths of this path set via a user-defined attribute. As path legs of assignment paths, volumes on these paths then enter with a correspondingly changed weight (Fundamentals: Signal coordination (Signal offset optimization)). If required, select the desired path set here. Weighting attribute for PrT paths Select the desired attribute for the weighting of the PrT paths. |
|
Use coordination group filter |
If this option has been selected, the coordination is executed only for the signal controllers of the selected coordination groups. The optimization is carried out individually for each group. You create coordination groups in the Network > Signal coordination groups menu (Creating a signal coordination group). You can then allocate signal controllers to coordination groups. |
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Use demand segment filter |
If the option is selected, only the assignment paths of the selected demand segments are taken into account. Click the button to select the demand segments you need. |
| Restrict time range for path volumes |
The setting is only relevant for results from SBA and PDV assignments. If you restrict the time range, the volumes of the signal groups are no longer determined from the AP volume of the paths, but from the time-dependent path volumes and extrapolated to one hour. If you do not restrict the time range, the AP path volumes are used. |
2. Make the desired changes on the Genetic algorithm tab.
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Cost function |
Specify the desired factors for weighting the wait time and the number of queued vehicles. |
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Number of initial solutions |
Enter the desired number of start solutions. |
|
Maximum number of iterations |
Specify the maximum number of iterations after which the procedure ends. |
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Maximum number of iterations without improvement |
Specifies the number of iterations after which the solution must have improved to continue calculating. |
| Minimum improvement per iteration | Indication of the minimum improvement per iteration in percent. |
3. Make the desired changes on the Platoon progression tab.
|
Travel times |
For each of the network object types, select a numerical attribute for path leg travel time calculation and enter a factor, if applicable. A travel time should be selected that does not include the delays that occur at the signal controllers (e.g. the travel time in the unloaded network t0). Just as you restrict path volumes to a time range, here you can select travel times from that time range either directly by selecting tCur of an analysis time interval or by aggregating over multiple analysis time intervals. Note The setting is only relevant for results from SBA and PDV assignments. |
| Hourly volume factor |
Specify a factor for conversion to hourly volumes. Note This setting is only relevant if you use path volumes from the analysis period (AP). |
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Maximum permitted vol/cap ratio for platooning [%] |
If this saturation is exceeded on a path leg link, the path leg is ignored for coordination, because no platoon is retained with too high saturation. |
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Minimum platoon index |
If the platoon index is below this threshold at the end of the path leg, the path leg is ignored for coordination, because the platoon is not distinct enough. |
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Calculate platoon progression according to Robertson |
Enter appropriate values for Alpha and Beta required by the platoon progression formula. |
4. Make the desired settings on the Split and cycle time optimization tab if you have activated optimization on the Basis tab.
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Use cycle times of coordination groups |
If the option is selected, the cycle times of the coordination groups are used. If the option is not selected, all cycle times are used according to the step size between the specified minimum and maximum cycle time. Also, enter the desired Increment for cycle time. |
5. Confirm with OK.
The signal offset optimization is carried out.
