Traffic Signal Information & Priority

Introduction

Traffic signals in the Nordic counties have been characterised by swift adaptions to fluctuations in traffic as well as efficient schemes for bus priority. In pursuing efficient local solutions, we have also partially forfeited common standardised solutions. Moving into a time of extended support by advanced driver assistance systems and autonomous vehicles, we seek to combine our flexible traffic signals with predictable traffic signal information and standardised priority.

Background

Providing predictable traffic signal information and standardised priority will allow vehicles to automatically adjust their behaviour without human interaction and is an important step towards the realisation of autonomous vehicles and a support to advanced driver assistance systems.

Objective

The flagship pilot will focus on implementation in an urban context. The main objective is to address and set-up ecosystems to achieve deployment of predictable traffic signal information and standardised priority.

Cities are interested in SPAT/MAP as a start-up for C-ITS applications. Both technical aspects as well as how to finance and organise the commitment create uncertainty and the flagship pilot will address these. Using existing and newly established areas with traffic light controllers sharing SPATEM/MAPEM messages in three countries, we aim to evaluate the possible ecosystems.

Many cities are in the process of deploying or have already deployed schemes for priority of e.g. public transport. By identifying common protocols for distribution of messages both from real time systems for public transport towards traffic signal systems as well as for distribution between the traffic signal system and controllers in intersections, we will develop common architecture and protocols to make a unified Nordic priority concept to be utilised for new installations: We will also demonstrate the system for requests for priority from vehicle to road operator in the pilot.

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Pilot Trials

Flagship pilot Traffic Signal Information – is building implementations in Goteborg (Sweden), Trondheim (Norway) and Tampere (Finland). The implementations will be a starting point for both technical verifications of prediction quality as well as user feasibility studies. 

The implementations are focusing on three areas

- Quality of predictions

- Behaviour changes of drivers

- Sharing predictions to enable a obtain a live service after Nordic Way 3.

For all implementations we are working towards quality of predictions that allow us to publish SPAT messages to OEM’s that can provide guidance to customer cars. The sharing can be done by both dedicated services from the OEM’s towards their own production cars as well as by data sharing from the Nordic Way 3 Interchange.

Testing of behaviour changes of drivers are done with a dedicated app integrated in Polestar 2 and Volvo XC40 Electric. They use the Google Automotive Application for infotainment system,which enables third-party suppliers to create information channels into the car of the driver and vehicle. NordicWay 3 is using this opportunity to show forecasts from traffic lights and warnings about roadworks directly in the centre console in Polestar 2 cars.

The intention of the development is to study any behavioural changes when the driver receives information about the status of the road in front of the vehicle.

Will there be speed adjustments or will the driver's interaction with the vehicle change? This can be used to analyse the driver's manoeuvring choices.

SINTEF is the research partner thatwill analyse possible changes in speed adaption due to C-ITS messages like GLOSA, TTG and RRW. 

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Testing with a selection of drivers will be performed first in Trondheim in February 2023 and thereafter at the other implementations. This will provide us with better insight into the effects of providing the information.

Flagship pilot Traffic Signal Priority

Traffic signal prioritisation for public transport has been in existence for decades. Some systems are already on their second or even third generation.

Previous solutions for traffic signal prioritisation relied on short-range communication and proprietary interfaces and data types.

The NordicWay 3 Traffic Signal Priority pilot is testing the existing open standards for traffic signal prioritisation, namely MAPEM and SREM/SSEM, along with the communication infrastructure that includes the Interchange Node.

The pilots sites support prioritisation for various types of traffic: emergency vehicles, public transport, and goods transport.

On-street testing is taking place in Stockholm and Uppsala.