Berlin is creating the infrastructure to enable better communications between vehicles and traffic signals, starting with the first C-ITS control to prioritise public transport.

C-ITS (cooperative intelligent transport systems) enables standardised digital information exchange between vehicles and traffic infrastructure, initially between buses and traffic lights.

The Berlin Senate Department for Mobility, Transport, Climate Protection & Environment (SenMVKU) has put the first Berlin traffic light systems with C-ITS-based control for public transport priority into operation on Schloßstraße in Steglitz. With this, the city is creating the infrastructural prerequisites for a new communication standard between vehicles and traffic infrastructure and is driving forward the digitalisation of traffic management, for example to reduce waiting times and to take individual requirements into account at an early stage.

The ITS-G5 radio standard, developed for fast and secure data exchange in road traffic, is used for direct communication. It is gradually replacing the previous reporting point transmission via digital data radio, which functions as a point-by-point registration of a vehicle at traffic lights. Based on this registration, the signal programmes are adjusted so buses can pass the intersection with little time lost. This communication only works in one direction. Feedback to the vehicle – for example, about the successful receipt of the registration – is not possible, nor is a real-time message if the approach is different than expected.

With direct communication via ITS-G5, buses and trams will receive feedback on the status and progress of priority signals and can be more precisely integrated into signal control. This enables smoother operation through less repeated braking and acceleration, or by allowing for a targeted extension of stop dwell times.

“A bus that no longer just knocks on the traffic light, but receives a response; that’s the difference C-ITS makes,” said Ute Bonde from SenMVKU (www.berlin.de/sen/uvk). “Until now, the vehicle has sent its request, and it remains unclear whether it has been received. With direct communication via ITS-G5, this becomes a genuine dialogue between the vehicle and the infrastructure. This allows public transport to travel more smoothly and with fewer disruptions through the city. Schloßstraße will show us how this technology works in everyday use.”

The standard also creates the basis for further applications such as the prioritisation of emergency vehicles, assistance systems for right-turning vehicles to protect cyclists, or green time predictions for cycling at the next traffic light.

“This lays the foundation for further applications, from right-turn protection for cyclists to emergency vehicle prioritisation,” said Bonde.

Eight traffic lights on Schloßstraße have been equipped with communication units and enhanced control systems. Starting this month, the function will be tested and evaluated under real-world conditions using BVG (Berlin Transport Authority) buses over several weeks and at various operational levels. The control systems support both the existing public transport priority system and C-ITS communication simultaneously. This is a prerequisite for the gradual transition.

With this project, the SenMVKU also supports the goals of automated driving and the greater integration of cycling and pedestrian traffic into traffic management, both in terms of data collection and as recipients of service messages. Furthermore, the expansion of C-ITS, while maintaining current cyber-security standards, should help the city monitor and analyse its own infrastructure.

BVG (www.bvg.de) is the project sponsor of the pilot project. Development and approval took place over two years in coordination with the relevant department of traffic management division, supported by the German Aerospace Center (DLR, www.dlr.de) and the Grün Berlin subsidiary GB InfraSignal (infrasignal.de). Technical exchanges with the city of Hamburg, which contributed technological expertise, was also part of the process.

With this, Berlin is taking a step towards a digitally networked transport infrastructure. The insights gained from real-world operation will be incorporated into the further development of the technical and functional framework and will form the basis for the continued expansion of C-ITS-based applications in Berlin’s transport network.