---
title: QueueOutput
---

The idea behind this output option is to detect the queue in front of
the controlled/uncontrolled junction. The queue length is calculated
using the end of the last standing vehicle.

## Instantiating within the Simulation

The simulation is forced to generate this output using the option **--queue-output** {{DT_FILE}}. {{DT_FILE}} is
the name of the file the output will be written to. Any other file with
this name will be overwritten, the destination folder must exist. Using the option **--qeue-output.period** {{DT_TIME}}, the times 
the queue lengths will be written can be restricted to the given period. Then, the other time steps will be skipped.

## Generated Output

The generated XML file looks like this:

```xml
<queue-export>

  <data timestep="<TIME_STEP>">

  <lanes>

    <lane id="<LANE_ID>" queueing_time="<LANE_QUEUEING_TIME>" queueing_length="<LANE_QUEUEING_LENGTH>"
    queueing_length_experimental="<LANE_QUEUEING_LENGTH_EXPERIMENTAL>"/>

    ... next lane ...

  </lanes>
  </data>

  ... next timestep ...

</queue-export>
```

| Name                           | Type                 | Description                                                                         |
| ------------------------------ | -------------------- | ----------------------------------------------------------------------------------- |
| time_step                     | (simulation) seconds | The time step described by the values within this timestep-element                  |
| id                             | id                   | The id of the lane                                                                  |
| queueing_time                 | seconds              | The total waiting time of vehicles due to a queue                                   |
| queueing_length               | meters               | Thus the length from the junction until the final vehicle in line                   |
| queueing_length_experimental | meters               | The length of the queue, thus until the last vehicle with a speed lower than 5 km/h |

## Notes

This output option should offer some information about the queues in
front of the junctions, which can be used in cases of routing or V2X
communications.

## Visualization example

### Queuing times over time

<img src="../../images/queue_out.png" width="500px"/>

Generated with [plotXMLAttributes.py](../../Tools/Visualization.md#queuing_times_over_time).
