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).

How does a Traffic Model relate to the Tygron engine?

Traffic in the Tygron Engine is based on where the roads are situated in the project area, and on the intensity of the traffic on these roads. To better visualize traffic and its impact in the Tygron Engine, three different traffic aspects are simulated: Traffic Flow, Traffic NO2 Pollution and Traffic Noise. These three aspects are visualized on their respective overlays.

Traffic Flow (Density)

Traffic density is measured by the amount of units per kilometer road section per hour. In the Tygron engine this is by default calculated on the basis of the location of the roads and road type (PDOK NBW) and the traffic intensities of these road sections (INWEVA 2015/VI-Lucht & Geluid), and can be changed by changing the amount of units per hour per road section.

Traffic NO2

Traffic NO2 refers to Nitrogen dioxide pollution caused by traffic. This is calculated by default by combining the data of the location of the roads and road type (PDOK NBW) with air quality data sets(NSL Monitoringstool/ VI-Lucht & Geluid).

Traffic Noise

One of the main sources of environmental noise in the Netherlands is road traffic. The Traffic Noise overlay displays the impact of these sounds generated by traffic on the surrounding area. This overlay is based on available data about traffic sound polution (VI-Lucht & Geluid).

The main purpose of the default traffic model in the Tygron engine is to simulate impact of traffic on the 3D World, not to simulate the traffic logistics.

Traffic Data 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 model is generated for the selected project area, based on available (open) data sources. This model is based on road location (NBW), road type (NBW), traffic intensity (INWEVA 2015/VI-Lucht & Geluid), air quality(NSL Monitoringstool/VI-Lucht & Geluid) and traffic sound polution (VI-Lucht & Geluid).

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). As a result, the NSL Monitoringstool is made available to provide air quality data.

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. This file is actualized every four years.

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

INWEVA 2015

INWEVA is short for INtensiteiten op WEgVAkken (traffic intensities on road sections). 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, and updated each year.

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

In januari 2016 the application was updated and actualized for the last time.

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 example as an indicator, 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