Plus+ traffic control system

A completely new approach to traffic signal control. Intelligent infrastructure improves resilience. Minimal cabling simplifies installation and cuts cost.

With financial and people limitations and increasing pressure on our congested road infrastructure it's no surprise to know that on-street engineering time is a major challenge for those responsible for traffic management.     

Get in touch with our Plus+ experts

Contact us now

Based on the proven ST950 Intersection controller, the ST950 Plussystem from Siemens Mobility no longer uses many individual connections between signal heads and controllers; instead it uses simple four core cables and intelligent communications to reduce the installation effort, as well as saving valuable resources.


By transferring to a Siemens Mobility Plus+ system from a traditional approach, the reduction in copper alone is astounding.  

Download our ST950 Plus+ brochure

Download the brochure now

First commission of Plus+ in Coventry

On June 24th 2020, Siemens Mobility successfully commissioned the first Plus+ installation in Coventry. The installation marks a major milestone for this ground-breaking traffic signal technology and we are delighted to see this intelligent infrastructure solution in full operation, delivering benefits to Coventry City Council, its traffic management team and of course, the city's road users.

With Plus+ being much quicker and easier to install, there is less risk and significantly less cost to the authority, enabling us to provide a better service to people who visit, live and work in our city.
Ben Gray, Highway Network Manager, Coventry City Council

Quicker and safer to install Plus+ compared to a traditional traffic control system:

Plus+ uses dedicated failsafe controllers, signal heads and pedestrian indicators as well as new smartloop modules ensuring that the overall system is tolerant of individual component and cable damage, resulting in higher intersection availability and reduced disruption to the travelling public.

Traditional traffic control systems use many cables to connect street furniture to the traffic controller. A distributed system uses intelligence spread throughout the intersection to significantly reduce individual cable connections.


  • Fewerlighter cables are needed
  • Cabling approach makes use of low-level access poles much easier
  • Cabling approach makes pre-assembly of poles and heads more efficient

All of these factors mean that there is potentially a significant reduction in on-street working time, meaning a quicker and safer installation.

Plus+ portfolio grows further

Our Plus+ traffic control solution meets another major development milestone with PCaTS (Pedestrian Countdown at Traffic Signals) added to the portfolio.


Further enhancements include:

  • Addition of phase mimics at the controller cabinet
  • Switched sign functionality
  • Pedestrian centre island blackout functionality
  • SmartLoop Android Phone and Tablet App release
  • ST950 family firmware update to V25
  • IC4 V15.4.4 (Available to download now)

The release will also see the completion of the trial of Plus+ Low Level Cycle Signals with these being released for limited sale with the full product release planned for Autumn 2021.

New SmartLoop Detector Solution from Siemens Mobility

A narrow swing bridge across the Kennet and Avon canal in Theale, West Berkshire has been the first commissioned site with our new SmartLoop detector solution.


While loop technology is well known in the industry, the SmartLoop is the next generation development with significant benefit.  By distributing the loop intelligence, SmartLoops avoid the need to wire each individual loop back to the controller reducing the amount of cabling and civil engineering works required - and the associated disruption for road users.



It's all in the detail

A completely new approach to traffic signal control.  Intelligent infrastructure improves resilience.  Minimal cabling simplifies installation and cuts cost. 

  • Increased safety on-street both during installation and day-to-day operation
  • Better Installation methods
  • Better diagnostics
  • Passively safe
  • Lower power
  • Highly resilient to external damage and internal component failure
  • Less working at height
  • Enhanced electrical safety
  • Less Traffic Management required
  • Reduced time on-street


JCT Symposium 2020 presentation video

Keith Manston, Head of Product Management gives a short overview of the Plus+ system: The next generation distributed traffic control.

System Overview

ST950 Plus+ and the dedicated failsafe components have been designed to be highly resilient to internal failure and external damage. If damage does occur to the traffic signals, individual nodes can be 'hot-swapped' typically allowing maintenance to be undertaken while the traffic signals remain switched on.

Combined with a design which is able to withstand short circuits that may occur during damage to in-street cables and redundant power supplies, Plus+ can make sure the intersection is kept available and operational during repairs or predictive maintenance.

As well as the advantages coming from the quicker and safer installation and the robust nature of the design, the Plus+ system also prevents a number of other problems that can prove costly or can in some cases, be dangerous:

  • Plus+ only supports ELV (Extra Low Voltage) eliminating electric shock risks on-street for both the engineer and the public
  • Inbuilt system self-checking allows protection against false signals being shown on-street due to error or deliberate acts

Plus+ offers several new components which facilitate the use of advanced system communication and reduced cable, including:

  • ST950 Plus+ controller
  • Helios Plus+ signal heads
  • Plus+ nearside indicators
  • Plus+ wait indicators

These retain the 'look and feel' of their standard ELV family members but include the necessary internal technology to support Plus+ operation.


In addititon to the standard components Plus+ introduces a new concept in loop detector technology. The Plus+ Smartloop places detection technology close to the actual detection loops and allow them to connect into the Plus+ communication and power network around a site, eliminating the need to loop feeder cables to be brought back to the controller cabinet.


Direct integration with above ground detectors, standard loop detectors and WiMag is also possible.

Register now to receive your monthly newsletter

Sign up now

Siemens Mobility Plus+ offers a powerful toolset to support and simplify the design, installation, commissioning and maintenance processes

To help simplify the design process, an AutoCAD Plug-In works alongside the widely used KeySignals site layout drawing tools to capture the full information about a junction's characteristics and component relationships. By calculating the full parameters for rings and arms (and identifying cable runs and node assignments are within design limits), the design process is made as efficient as possible. On completion of the design process, an equipment inventory and controller capacity specification is provided.   The tool set allows the installer to use the data from the design process to map physical signal heads and nodes to their use and geographical location. If needed the engineer can then adjust the configuration during installation to adapt to last minute on-site challenges or physical environment factors.   This is all backed up with bar-code scanning to ensure correct identification of components.

Enhanced ST950 Plus+ design and configuration suite

Find out more


Addressing the safety and availability challenges when delivering distributed Traffic Control systems

We explore the safety and system challenges which have been successfully addressed in the Siemens Plus+ system, to ensure that a distributed Traffic Control system delivers both savings in on-street implementation as well as maximum on-going availability under a wide range of possible fault conditions.

This topic was presented at the JCT Traffic Signal Symposium & Exhibition

Download presentation

Let us help you improve your traffic network

Developed by Siemens Mobility to deliver on-street resilience and reliability, as well as fast and cost effective installation for both new and refurbished projects, Plus+ can reduce overall installation and maintenance costs and increase intersection availability.  By drastically reducing the raw materials, cabling and people resource required compared to traditional systems, Plus+ is an environmentally friendly solution that minimises installation time, thereby improving site safety and reducing disruption.

Get in touch with our experts

Contact us now