In PT, functions must be provided to ensure that the control system runs smoothly even if the PT request does not run according to plan. A non-scheduled process occurs on the one hand in the event of faults in the recording system or on the other hand in the event of faults on the access route (e.g. traffic jam). For these cases, vs | plus provides the two functions forced request and forced cancellation.
As an addition to the request for a traffic stream, vs | plus internally determines traffic stream attributes. Depending on the remaining journey time, a decision is made for each PT traffic stream as to how it can influence the control system. The following questions arise:
- If a PT arrives in a request area?
- If the remaining travelling time is sufficient to initiate a stage change?
- If conflicting traffic streams need to be blocked?
- Must the main request be initiated?
- Must the stage change be initiated?
A so-called PT prioritisation module next decides what to do with the requested PT´s. The following questions arise:
- Should the requested PT be prioritised?
- Which public transport traffic streams need to be taken into account in the event of a simultaneous conflicting requirement?
- Is a public transport traffic stream to be prioritised immediately with a simultaneous friendly request?
- How should a follow-up train be treated?
The result of these modules is an identifier that determines whether a PT traffic stream is requested and also determines whether it should be prioritised.
It is important to note that after processing by these modules, only those PT traffic streams that are conflict-free (traffic streams that are not conflicting with each other) are prioritised.
The further treatment of PT corresponds to the standard processing of traffic streams. An application is generated from the request in traffic stream processing in accordance with the frame signals.
The PT traffic stream is then taken into account in the control management, according to its class allocation and level.