“If connected vehicles are to work in everyday life, they need to speak the same language. Without interoperability, technology stops at pilot projects,” says Katrin Sjöberg, Chair of ETSI TC ITS WG4 and Technical Advisor at Volvo Autonomous Solutions.
The potential is substantial: greater safety, fewer accidents, smoother traffic and entirely new mobility services. Yet it all depends on one crucial condition – that the systems work together. Interoperability is the foundation, and standardisation is the route to achieving it.
Article in short:
Connected and automated vehicles can only become reality if they can communicate across manufacturers and national borders. Interoperability is therefore the basis for safety, innovation and fair competition. Without standards, technology risks getting stuck in pilot projects, markets become distorted and traffic safety is put at risk. ETSI’s work on C-ITS standards is vital to building systems that function in practice. For Sweden, active participation offers a chance to strengthen exports, turn research into practical solutions and secure a more sustainable, competitive future.
Katrin Sjöberg, Volvo Autonomous Solutions
Interoperability in connected vehicles – what it means in practice
Cooperative Intelligent Transport Systems (C-ITS) describe how vehicles communicate with one another, with infrastructure and with other road users. Internationally, the terms CAV (Connected and Automated Vehicles) and CCAM (Connected, Cooperative and Automated Mobility) are also used.
“At ETSI we talk about C-ITS, but essentially it means the same thing – vehicles exchanging information with each other and with infrastructure to improve road safety”, says Katrin Sjöberg.
Fact box: key concepts in C-ITS
V2V (Vehicle-to-Vehicle): Communication between vehicles.
V2I (Vehicle-to-Infrastructure): Communication between vehicles and smart road infrastructure such as traffic lights or signs.
V2X (Vehicle-to-Everything): A collective term for communication with all types of units in the transport system.
C-V2X (Cellular Vehicle-to-Everything): Short-range communication between vehicles and smart infrastructure based on 4G or 5G technology. (When C-V2X uses 4G it is also called LTE-V2X.)
DSRC (Dedicated Short-Range Communications): Wi-Fi-based technology for short-range communication between vehicles and infrastructure. In Europe, DSRC is known as ITS-G5.
Technical challenges: several systems must work together
The challenge is not to develop one specific technology, but to make different technologies and interests work together. Today’s connected vehicles can use 4G- or 5G-based C-V2X, Wi-Fi-based DSRC (ITS-G5) and future hybrid solutions. Yet every manufacturer, region and industry body has its own priorities. The result is technical fragmentation that hinders interoperability and drives up implementation costs.
“We have the technology, but different regions and manufacturers are pulling in different directions. Without a shared vision, every solution becomes an island,” says Katrin Sjöberg.
The problem is not purely technical. Different parts of the world have taken different approaches: the EU is technology-neutral in principle, and current commercial use mainly relies on DSRC (ITS-G5). The US, which historically prioritised Wi-Fi-based DSRC, has now shifted towards LTE-V2X, incorporated into spectrum regulation as a technical requirement. China has developed its own national implementation of LTE-V2X with dedicated frequencies and requirements. The system is being rolled out on a large scale and works well domestically, but it is not fully compatible with European or American solutions
The consequences become clear when technology meets reality. A truck that can communicate seamlessly between Gothenburg and Madrid may not necessarily work in Shanghai or Beijing. The lack of global coordination forces companies that export vehicles and services to adapt to multiple standards – a costly and complex process.
Beyond the technical fragmentation, there is also a time factor. Vehicles remain in service for decades, while communication technologies evolve in short cycles. Standardisation is therefore crucial to make the technology sustainable over time.
“It’s a major challenge. A vehicle should be able to run for twenty years, but the communication technology may be updated in five-year cycles. That means the standards must stand the test of time,” says Katrin Sjöberg.
Risks when standardisation of connected vehicles is lacking
When standardisation fails to keep up, three serious risks arise that affect safety, competition and innovation.
Safety risks. If vehicles cannot communicate reliably, safety is the first aspect to be compromised. If one vehicle warns of an accident but a following vehicle cannot interpret the message in time, the system fails when it matters most. At intersections, differing interpretations of the same traffic data can cause confusion rather than coordination.
Distorted competition. When standards are missing, markets tend to lock around proprietary solutions. A city that invests in a closed system risks dependency on a single supplier – raising costs and limiting innovation. Smaller players and SMEs struggle to compete because they lack the resources to adapt their products to multiple technical environments.
Innovation stuck in pilot projects. Many advances in connected-vehicle technology work in controlled tests but never reach full implementation. Without standards to ensure compatibility, projects remain fragmented.
How ETSI’s C-ITS standards contribute to interoperability
Standardisation is the tool that makes interoperability possible. C-ITS is not a single standard but a field encompassing multiple standards and specifications defining how vehicles and infrastructure communicate. ETSI has a central role in this work.
As Chair of ETSI TC ITS WG4, the working group for vehicle communication, Katrin Sjöberg has helped shape these standards.
“What makes ETSI unique is that every voice is taken seriously, whether it comes from a global corporation or an individual researcher. The consensus model leads to solutions that actually work in practice.”
Why more voices are needed – especially from SMEs and academia – is something we explored in a previous article: Participate in standardisation – why more voices are needed
“For us at Volvo, it’s essential that a vehicle built in Sweden works just as well in Germany as in China. That’s why we’re actively involved in shaping the standards,” says Katrin Sjöberg.
To ensure that standards work in the real world, dedicated testbeds and datasets are used. One example is the work carried out at NIST (National Institute of Standards and Technology), the US authority for standards and technology, which has developed C-V2X interoperability tests for both vehicles and roadside units.
In Europe, ETSI plays a similar role through its Plugtests™ – hands-on interoperability tests where manufacturers, operators and research organisations verify that different implementations work together. The purpose is to identify technical barriers at an early stage, feed results back into the standardisation process and ensure that the final standards work seamlessly across vehicles, roadside equipment and infrastructure systems (ETSI, 2025).
Why Sweden must participate in the standardisation of connected vehicles
For Sweden, interoperability is more than a technical detail – it is a strategic opportunity that affects industry, research and society alike.
For industry, it means that Swedish companies can export solutions that work globally, not just nationally. Volvo and other actors in the automotive sector stand to gain from being part of international standardisation.
For research, it opens up collaboration and international projects where new knowledge can be put into practice. It also creates opportunities for funding through programmes such as Horizon Europe, which rewards projects that link technical development to standardisation.
For SMEs, participation in standardisation can be decisive. Many of the most innovative solutions, from new sensors to advanced software, come from small companies. Without influence over standards, their solutions may never become compatible and thus never reach the market. When SMEs take part, their innovations can spread globally on equal terms.
For society, it’s a matter of safety, efficiency and sustainability. When vehicles communicate with traffic lights and infrastructure, both accidents and energy use decrease.
A recent study shows that vehicles interacting with roadside units at intersections can reduce unnecessary stops and improve traffic flow, shortening journeys and lowering emissions (arXiv, 2024).
For individual drivers, interoperability may seem abstract, but in practice it determines whether the technology works day to day. “A connected vehicle that cannot communicate with infrastructure won’t warn you of a red light in time. A car that cannot interpret data from a foreign system may lose functions on holiday,” says Katrin Sjöberg.
If Sweden fails to stay involved, we risk becoming dependent on standards set elsewhere. We would then have to adapt to rules we had no part in shaping – and lose both competitiveness and influence.
Stronger competitiveness when more actors get involved
Katrin Sjöberg is clear that interoperability doesn’t happen by itself. “To create real value, we need standardisation, and that means more voices in the process.”
When different perspectives from industry, academia and the public sector come together, the result is solutions that not only work technically but make a difference in practice.
“It’s both technically challenging and hugely rewarding to work within ETSI,” she concludes.
Your involvement can be the difference between isolated pilots and fully functional international systems. Read more about what it’s like to be an active member of ITS.
In the next part of this series, she shares her journey – from doctoral student to chair of an international working group.
