Dublin’s Centralised Public Transport Priority System

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In Dublin City, day to day traffic management is provided via SCATS (Sydney Coordinated Adaptive Traffic System), Dublin City Council in partnership with Nicander have developed an interface module for the purpose of implementing a Centralised Public Transport Priority system. This module allows buses to communicate with the SCATS system resulting in reduced journey times for passengers.

Centralised Bus Priority User Interface, showing virtual detectors and buses being tracked by the system.

Previously for buses, isolated units were designed and utilised to provide priority. These units would be installed on site adjacent to the local traffic controller. They would detect the approach of a bus using close radio communications configured on proximity settings. Once a bus was detected, the local traffic controller would be configured to provide bus priority by bringing in a “Hurry” call to immediately bring up the green signal; this would cause the mode of operation to change from Masterlink to Isolated mode in order to service the bus. This would cause the junction to lose coordination with other junctions.

Dublin Bus automatic vehicle location system provides a data feed which contains the position of each in-service bus in the fleet at a polling period of approximately 20 seconds. Data on whether the bus is in congestion or not, and if the bus is loading passengers at a bus stop is also contained in this data feed. With the DPTIM (Dublin Public Transport Interface Module) application for the SCATS system, this offers the possibility of a centralised network response to bus problem locations, not just an individual junction response but to corridors and city-wide routes via multiple junction adjustments.

DPTIM interventions allow intersections within SCATS to be configured due to the presence of buses. Users create virtual detectors which prioritise buses when a set of specified attributes have been satisfied. As a bus approaches an intersection and enters a virtual detector, a DPTIM intervention is activated and the application communicates with SCATS, priority is then provided via a number of different techniques. One such technique is through the application of an action list which has SCATS call a split plan which provides more time to a specific phase; in turn this enables the bus to pass through the intersection quicker as more green time has been allocated to the phase which allows it to proceed. The techniques used for bus priority ensure that intersections stay coordinated and synchronised in their traffic movements in the adaptive environment that SCATS provides. There are currently 400 plus bus priority intervention measures configured across Dublin City and surrounding areas, either on routes to ensure consistent level of service or at known pinch point areas.


Virtual Detectors in operation

Virtual detectors are drawn onto the application, when the bus moves into this virtual detector the signal timings are changed to allow the bus to progress.

Plan 8 is locked into the junction ahead of the bus giving the majority of the time to the side road allowing the bus to clear the junction:

Example of a location identified for bus priority


  1. Bus position data shows bus is making very slow progress.
  2. Virtual detectors are drawn onto the application to trigger bus priority.
  3. Bus position data shows that progress is improved through the junctions.

Presentation on Data Driven Decisions for Centralised Bus Priority in Dublin City


The bus priority project is fully funded by the National Transport Authority