Traffic Light Priority in Central and New Lincolnshire
Traffic Lights

Traffic Signal priority feeds can be supplied to UTMC / UTC systems using RTIGT031 or bespoke format if required. To achieve priority each bus requires information to be available to the ETM or AVL system to enable it to send a priority request message over its GPRS/3/4G data connection. For each junction a number of trigger locations are typically setup, a minimum of one point before and one after for a clear down message is required.

The format for these trigger locations varies between ETM and AVL suppliers for example the file format for Stagecoach / VIX is different from Ticketer. We support all the main formats in use by suppliers who support TLP from an ETM. This approach was developed and tested by Ticketer and VIX ETMS in South Yorkshire and is now increasingly widespread. The priority request message from the bus is received by our central system which determines which UTC system to forward the request onto. All TLP request data is retained by Nimbus to enable post event analysis to review the effectiveness of the trigger locations enabling evidence based adjustments to be made.

The current solution where a signal controllers is not connected to a UTC relies on a PMR transmitter in each vehicle which is increasingly uncommon as ETMs become the AVL source of choice. We can supply, if required special, unique to Nimbus, TLP units for traffic signal controllers that support the use of RTIGT031 centre to centre data feeds without the use of UTC enabling a wider range of vehicles to obtain signal priority and for standalone signal controllers to continue to support bus priority. This is currently being implemented in our Lincolnshire system and can be replicated to enable continued provision of traffic light priority at the existing local junctions. There is no requirement for any additional equipment on bus or a UTC system connection.

This image shows the configuration of an Eastbound approach to George Street TL in Reading showing where the junction is as well as the trigger points:

This image shows actual traffic signal request activity (green equals approach trigger point, yellow passed trigger point, orange on junction, red clear down):