ITS can relieve road congestion and minimise CO₂ emission

Traffic and transportation planning Insights

Urban areas across the world are facing major traffic challenges due to increasing congestion and ever-increasing CO₂ emissions from transport. Intelligent transport systems (ITS) may be part of the solution.

More people are moving to the world's cities. According to UN forecasts, by 2050, 6.4 billion people will live in cities across the world, which corresponds to 66 per cent of the global population.

This development will undoubtedly increase the pressure on mobility and air quality in cities. Today, vehicular traffic in cities already accounts for 23 per cent of the total global CO₂ emission, and if this trend continues, the share will reach almost 60 per cent by 2050.

Regulating traffic in urban areas is a delicate balance between impact, functionality, accessibility, safety and sustainability. And in many big cities, a lack of free space rules out the possibility of expanding the road network, so alternative methods are needed.

Sensors and computer technology wrestle with congestion

One of the technologies that can help tackle traffic challenges in cities are so-called intelligent transport systems (ITS), which make use advanced sensors to collect data and computer and communication technology.

The objective is to minimise road congestion, improve traffic safety and mobility, and to reduce the environmental footprint. ITS is not merely applied to vehicular traffic: It is also a tool for regulating pedestrian and bicycle traffic as well as public transit.

There are several definitions of ITS, which cover a range of tools. The best known include navigation systems, dynamic traffic information via different channels, road signal systems and automatic payment systems (parking payment, road pricing, tolling), but in its widest sense, ITS can also include technologies such as autonomous vehicles.

ITS is used across much of the world and there are numerous examples of how ITS relieves local and global problems.

40 per cent fewer traffic accidents

One case is Bologna, Italy. Bologna wanted to reduce traffic accidents and personal injuries. A large study showed that 83 per cent of traffic accidents were caused by poor driver behaviour. The solution was to implement an automatic reinforcement system, Star, in a number of intersections. Cameras were installed, directly transmitting information about traffic violations to the police.

The hope was to minimise poor driver behaviour. And it worked. Within one year, the IT solution resulted in 40 per cent fewer traffic accidents and 48 per cent fewer personal injuries.

Another case is Venice and the nearby town of Mestre, Italy. Both were struggling with tailbacks and poor air quality. Therefore, both areas were turned into congestion charge zones for cars in 2011. An ITS solution made it possible to automatically and more easily register passing cars.

The congestion charge zone led to a ten per cent reduction in vehicular traffic in the cities, in turn meeting the targets of less congestion and better air quality.

contributes to reaching climate targets and reducing travel time

COWI is currently working on several major ITS projects, in Denmark and abroad. The Danish projects include the ITS programme in Copenhagen and the tender for OCIT-based solutions in Aarhus.

The Copenhagen ITS programme consists of several sub-elements: One being the City of Copenhagen's wish to cut travel time in nine selected traffic corridors and to meet the City's climate target of being CO₂ neutral by 2025.

The initiative is expected to increase passability for buses and bicycles in certain traffic corridors, and contribute to reducing the annual CO₂ emission by 25,000 tonnes after 2025. In comparison, the total traffic emissions amounted to some 380,000 tonnes in 2010.

To solve that challenge, CTMS (central traffic management system) is applied. An ITS solution which, based on live traffic data, regulates intersections in nine selected traffic corridors, depending on who they want to give priority. For instance, by creating green waves for cyclists and buses so they do not have to stop at a red light.

Doing this, ITS increases the mobility of selected road users and minimises their travel time, which may help render buses and bicycles more attractive means of transport.

Another ITS solution in Copenhagen is the installation of on-board units in lorries and road-site units in intersections.

The goal is to use the communication between the two units to, e.g., extend green time to minimise the stopping and starting of lorries in intersections, and thereby reduce CO₂ emissions. A similar system is already used by buses across Denmark.

The preliminary results of the mentioned ITS initiatives in Copenhagen include:

  • Reduction of travel time by as much as two minutes on some bus lines at peak hour
  • Reduction of travel time by as much as 30 seconds for cyclists in some corridors
  • Fewer stops for cyclists

Time-savings on longer sections may naturally be greater, depending on the route, and may thereby be a decisive factor when choosing your means of transport. 

Easier access to big data opens new possibilities

What makes ITS particularly interesting is the possibility of using relevant traffic data to a higher extent, which has become easier to collect, thanks to digitalisation and the development of new technologies.

ITS is seeing rapid, exciting development. And what may seem impossible today may be possible further down the line, as new technologies and tools for collecting data are developed. Autonomous vehicles and artificial intelligence are but a few technologies that are likely to be part of the ITS of the future.

Another key component of future tools is improved navigation systems. Today, navigation systems help people get from A to B based on data from one means of transport; However, the technology of the future, called MaaS (mobility-as-a-service) can gather integrated, platform-based solutions on a single platform.

The platform will give access to different means of transport and transport services via digital infrastructure. Technology may also be a means to suggest alternative means of transport to citizens, thereby promoting green means of transport.

Several decision makers at political, state and municipal levels are becoming aware of the possibilities of ITS. But since they are less visible than new roads and bridges and generate smaller traffic improvements, ITS is sometimes given low priority.

Nevertheless, ITS is less costly than major road projects, making it an important and innovative solution to future mobility problems.


I'm a traffic planner specialising in capacity analyses. Today, I act as project manager of the Copenhagen ITS project and have contributed to developing the solutions.

I'm interested in ITS because it will be part of the future, since new technology and access to relevant data allow for a wide range of interesting digital solutions to increasing mobility in society.

My ambition is to ensure that COWI is at the forefront of the development of smart ITS solutions.


I'm a traffic planner, but throughout my career I've been involved in ITS.

I initially focused on ITS because I wondered whether there was not a smarter way of solving traffic problems than by applying traditional construction solutions.

I've always been interested in identifying the best solution, optimising and pinpointing new solutions – that's what drives me every day.

Get in contact

Rasmus Guldborg Jensen
Vice President
Urban Planning and Transport, Denmark

Tel: +45 56401988

Get in contact

Jens Toft Wendelboe
Chief Project Manager
Urban Planning and Transport, Denmark

Tel: +45 56401146