Traffic Model

What is a Traffic Model

From Wikipedia, the free encyclopedia

A traffic model is a mathematical model of real-world traffic, usually, but not restricted to, road traffic. Traffic modeling draws heavily on theoretical foundations like network theory and certain theories from physics like the kinematic wave model. The interesting quantity being modeled and measured is the traffic flow, i.e. the throughput of mobile units (e.g. vehicles) per time and transportation medium capacity (e.g. road or lane width). Models can teach researchers and engineers how to ensure an optimal flow with a minimum number of traffic jams.

Traffic models often are the basis of a traffic simulation.

How does a Traffic Model relate to the Tygron engine?

To better visualize traffic and its impact in the Tygron Engine, three traffic aspects are simulated: Traffic Flow, Traffic NO2 Pollution and Traffic Noise. The main purpose is to simulate impact of traffic on the 3D World, not to simulate the traffic logistics.

Traffic Models available in the Tygron Engine

The Tygron Engine makes, by default, traffic based calculations for results such as the Traffic Flow overlay, the Traffic NO2 overlay and Traffic Sound Pollution overlay. These calculations are based on many different data sets. These data sets are different for each location/ country.

Data Sources

When creating a new project based on real data in the Tygron Engine, a standard traffic flow is generated for the selected project area, based on available (open) data sources. For the Netherlands these sources are:

NSL Monitoringstool

The Dutch governement, provinces en local authorities cooperate to improve the air quality. This is done under the umbrella of het Nationaal Samenwerkingsprogramma Luchtkwaliteit (NSL).

See also: https://www.nsl-monitoring.nl/

PDOK NBW wegen (Nationaal Wegen Bestand)

'NWB-Wegen' is a digital geographical file containing almost all roads in the Netherlands. Included are all roads that are managed by the national government, provinces, municipalities and water authorities, but only when these roads are assigned a name or number.

See also: https://www.pdok.nl/nl/service/wfs-nwb-wegen-nationaal-wegen-bestand

INWEVA 2015

INWEVA is short for INtensiteiten op WEgVAkken (road section intensities). Traffic intensities are measured on ca. 3000 road sections. For the other sections intensities are estimated, based on traffic modeling. The data are yearly averages per road section.

See also: https://nis.rijkswaterstaat.nl/portalcontent/logon/p2_33.html

VI-Lucht & Geluid

VI-Lucht en Geluid is a Dutch tool that provides the following data for a specific section of a road:

• An average traffic intensity expressed in motor vehicles per week day, per average daytime hour, per average evening hour, per average nighttime hour
• The share and size of medium heavy and heavy freight traffic
• The share and size of bus traffic

See also: https://www.infomil.nl/onderwerpen/klimaat-lucht/luchtkwaliteit/slag/hulpmiddelen/inschatten/

How to add a Custom Traffic Model to a project

Besides using the default traffic calculations, it is also possible to add a custom traffic model, better suited for the project case. A custom Traffic Model can be added directly as a static model, or as areas for a dynamic model.

In order to upload a custom traffic model, it has to first be properly prepared as a Geojson file, in the correct coordinate system.

See also: http://support.tygron.com/wiki/Geojson

Adding a Static Custom Traffic Model

A static model does not change (over time), when changes occur in the 3D world.

To upload a Traffic Model directly as static data, a prepared Geojson file can be dragged and dropped on the Editor window. A panel appears, where the option "Import Building Values" needs to be selected. The Geojson file has to contain an attribute named 'TRAFFIC_FLOW" (vehicles/ hour), so that constructions that are touched by sections of the traffic data, are given the value of the attribute belonging to that section.

How to add a Static Custom Traffic Model:

1. Drag and drop a prepared Geojson file on the Editor
2. Select "Import Building Values" from the "File Handler" panel
3. Ensure the attribute TRAFFIC_FLOW is activated on the "Import Building Values File" panel
4. Select the "Send" button on the same panel

• Editor.jpg

  Drag and drop a prepared Geojson file on the Editor

• ImportBuildingValues.jpg

  Select "Import Building Values" from the "File Handler" panel

• SelectTrafficFlowAttr.jpg

  Ensure the attribute TRAFFIC_FLOW is activated

• ImportBuildingValuesFileSend.jpg

  Select the "Send" button

Adding a Dynamic Custom Traffic Model

A dynamic model changes (over time), according to changes in the 3D world.

To create a dynamic Traffic Model, the same Geojson file can be used. In this case "Import Areas" is selected on the File Handler panel, in stead of "Import Building Values". The sections of the Traffic Model will then be assigned to the project as areas. Next an excel file can be added, for an indicator or overlay, which updates constructions dynamically. To change the Traffic Model, a TQL statement such as the following can be used:

UPDATE_BUILDING_TRAFFIC_FLOW_WHERE_AREA_IS_6 (This statement updates the attribute "TRAFFIC_FLOW" (vehicles/ hour) of constructions located in Area 6.)

The excel implementation of a light Dynamic Traffic Model as described above, consists of the following consecutive steps:

• Retrieval of the original traffic density in Area X - SELECT_ATTRIBUTE_WHERE_NAME_IS_TRAFFIC_FLOW_AND_AREA_IS_X
• Calculation in an excel file, with the new traffic density as outcome - original traffic density + change
• Output of the new traffic density for constructions in Area X - UPDATE_BUILDING_TRAFFIC_FLOW_WHERE_AREA_IS_X

How to add a Dynamic Custom Traffic Model:

1. Drag and drop a prepared Geojson file on the Editor
2. Select "Import Areas" from the "File Handler" panel
3. Ensure the attribute TRAFFIC_FLOW is activated on the "Import Areas File" panel
4. Select the "Send" button on the same panel

• Editor.jpg

  Drag and drop a prepared Geojson file on the Editor

• ImportAreas-FileHandler.jpg

  Select "Import Areas" from the "File Handler" panel

• ImportAreaFile.jpg

  Ensure the attribute TRAFFIC_FLOW is activated

• ImportAreaFileSend.jpg

  Select the "Send" button