An event is classified as lane blocking if it:
- Assigns the number of operational lanes of a link to a value > 0 and is lower than the original number of lanes.
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Assigns the capacity of a link to a value > 0 and lower than the original capacity. In this case, the number of operational lanes is derived from the formula:
NumberOfOperationalLanes = RoundUp(NumberOfOriginalLanes * EventCapacity/OriginalCapacity)
For more details about the attributes composing this relation, see DATEXIISchema_2_2_2.xsd.
Important: Differently to a link-blocking event, a lane blocking never completely blocks a link and does not influence the available paths.
A lane blocking event:
- Inserts blocked vehicles on the number of blocked lanes of an affected link according to the temporal and spatial validity of the event (Figure 9).
- Creates vehicle attribute decisions to set the desired vehicle lane the first remaining open lane (see PTV Vissim manual, Defining vehicle attribute decisions).
In the figure, a lane-blocking event in PTV Vissim (red vehicles).
A lane-blocking event is split into 3 sections:
- Weaving: a section required to allow incoming vehicles to properly merge with the remaining lanes. This section becomes more important if multiple lanes are blocked.
- Blocking: the section covering the spatial extent of the event information.
- Emergency stop: a required section after the end to allow vehicles to use the (re)opened lanes.
The emergency stop is important if the end of the blocking section is close to a downstream intersection with reserved right turn lanes. It must be further away from the downstream end of the link than the emergency stops of the downstream connector links.
Modeling a lane blocking event
The modeling of a lane blocking event is based on the listed steps:
- Deleting all vehicles on all lanes in the weaving and blocking sections.
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Blocking the lanes with blocking vehicles.
- All blocked lanes of the blocking section are completely filled with blocking vehicles. N lanes are blocked, starting from the rightmost lane for right-side traffic (and vice versa for left-side traffic).
- The weaving section is split in N sections, where N is the number of blocked lanes. Each section has hard coded length of 10 meters. Moving every section upstream blocks one lane less than the previous section.
- Adding vehicle attribute decisions for all sections in the weaving section that change the desired lane of vehicles to the first unblocked lane.
- Adding vehicle attribute decisions at the end of the blocking sections that remove the desired lane of vehicles.
In the figure, you can see the spatial sections with blocked vehicles and vehicle attribute decisions (vertical lines).
Managing spatial sections
Depending on the number of blocked lanes, the weaving and emergency stop sections require a specific amount of space along the link.
If there is not enough space, the blocking section is shrunk. If it cannot be shrunk enough to accommodate enough space for the weaving and emergency stop sections, the event is discarded.
This is logged as a warning and decreases the reliability indicator of the micro simulation request (see → Reliability).
Lane blocking events can stretch over pocket lanes.
Overlapping lane-blocking events stack with each other.
For example, roadworks may reduce the number of operational lanes from a 3-lane road to 2 lanes. In case of an accident happening along the roadworks, the number of operational lanes may further reduce to 1 on a shorter section.
Therefore, the weaving section of the encompassed “accident” event is fused with the blocking section of the “roadworks” event (not shown in the figure).
Known special cases
Overlapping blocking vehicles in changing sections or for overlapping events.
When you block vehicles of different sections (for example, weaving and blocking sections), they may overlap. This is has no impact on the simulation results, it only affects the visualization.
Blocking vehicles not aligned with the shape of link.
When you block vehicles, they can be placed so that their shape does not align properly with the shape of the link. This is has no impact on the simulation results, it only affects the visualization.
Lane blocking events can delete overlapping events of vehicles blocking.
When a lane blocking event ends during the simulation period, a script deletes the blocking vehicles within the spatial extent of this event. This can also delete blocking vehicles of other lane or link blocking events covering the same space.
The likeliness for this happening is low, because it requires 2 overlapping events ending within the simulation period (with a significant impact on the simulation but very low probability).