First, you have to set specific virtual gates and lanes in your video. You need to define the waiting gates and lanes represented by entry gates and lanes (green) on the edges of the roundabout or intersection and blocking gates and lanes represented by neutral gates and lanes (blue) within the intersection or roundabout. The setup of entry and neutral gates for gap time and time to follow analysis can look like the definition you see in the image below.
Now you are ready to set your own Node which is necessary for defining the relationship between waiting and blocking gates/lanes. Click Add Measurement Node in the main menu and set the waiting gate/lane and blocking gate/lane in the right-bottom menu. Following our example from the image above you would need to set up the following:
Waiting Gate = Entry Gate 1
Waiting Lane = Entry Lane 1
Blocking Gate = Neutral Gate 1
Blocking Lane = Neutral Lane 1
To get gap acceptance time for the vehicles incoming from Entry lane 1 onto the roundabout.
You can set as many nodes as you want and export data for all nodes at once. Once you are done with setting up the nodes, Confirm Annotation Redefinition, and apply changes in Annotation Configurations. Now everything is ready and you can export the data to a .CSV file. To do the export go to the top menu and under Analysis use the Export Gap-Time/Time-to-Follow Data option. Next, a table will pop up where you can either keep the default values or you can set your own values as shown in the picture below. When you are happy with the export settings, click on the export button.
The export you get will include columns with the following data:
Unique Event ID - Unique ID of an event.
Measurement Node ID - Unique ID of the node that you have set.
Waiting Gate ID - Unique ID of the waiting gate that you have set.
Video Position of First Blocking [ms] - Video-time, when a vehicle was detected as a blocking one (passed a blocking gate).
First Blocking Vehicle ID - Unique ID of the first blocking vehicle that has passed the blocking gate.
Second Blocking Vehicle ID - Unique ID of the second blocking vehicle that has passed the blocking gate.
The number of Waiting Vehicles - Number of vehicles in the waiting lane, waiting to enter the roundabout/intersection.
First Waiting Vehicle ID - Unique ID of the first vehicle in the waiting lane.
Tg Value [ms] - Gap time - distance between the first and second blocking car in ms.
The number of Left Waiting Vehicles - How many cars there are left in the waiting lane after the first blocking vehicle passed.
First Left Waiting Vehicle ID - ID of the first vehicle that left the waiting lane and could continue to the roundabout.
Entered Vehicles Count - Number of vehicles that have left the waiting lane during gap time.
In case the gap time is sufficient enough for more than 2 vehicles to enter the waiting lane, the following columns are repeated:
(If Entered Vehicles Count > 1: list(Tf Value [ms])) - time to follow for the additional vehicles that left the waiting lane to join the main one.
Reaction Time [ms] - Reaction time of the following vehicle in the waiting lane.
Following Entered Vehicle ID - Unique ID of the followed vehicle in the waiting lane.
Video Position of Following Vehicle Entry [ms] - Time, when the first waiting vehicle left the waiting queue and the following vehicle became the first waiting vehicle.
Table export - part 1.
Table export - part 2.
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